Help with speed of advancement

Alrighty so, as I write this I'm 32 seasons (8 years) away from ending my second campaign on Hard.

This time I'm using the Date. The last one, I played as Shimazu.
At the moment I control 12 provinces, including all my victory condition ones except for Kyoto.
I do not foresee winning this campaign. My longtime ally, Uesugi, currently also holds 12 provinces, is listed as having "terrifying" strength (while I'm just 'strong'), and covers the entire quarter of the island from coast to coast, cutting me off from Kyoto. I have four provinces right above Kyoto that are my only holdout west of Uesugi lands, and that's where most if not all of my marshalling strength is forced to come from (although I DO have an army coming from Uzen on a fleet to help with a pincer move.)
Uesugi and I are locked in a bloody war against the Hattori, and have both taken quite a beating. Kenshin is dead, as Terumune. We're both running out of heirs, far as I can tell (from ninja intel) and our armies have both taken quite the beating(s). As of last turn, before I got off, Uesugi had one fairly healthy full stack of 10 yari ashigaru, 4 light cavalry, and 5 katana samurai, as well as a smaller stack of heavily-damaged units (3 yari samurai, 2 bow samurai, 1 naginata cavalry). I JUST won a heroic victory against a massive Hattori force (my one full stack led by my heir against 3 full Hattori stacks). While I only lost 2 units, the others are damaged and I'm afraid Hattori will attack me again with their FOURTH full stack as soon as I press the "next turn" button.
While I believe we just managed to break the power of the Hattori, with Uesugi so gosh-darn greedy for land I'm assuming I won't get 11 provinces by the time I get to Kyoto.
Point is, I'm gonna have to play perfectly, AND not have any more friggin Ikko Ikki revolts in Echizen in order to win. And then it's still a question of whether I'll have the military strength to take Kyoto.

Almost this exact same thing happened to me last game. Different allies and enemies and all, but as Shimazu I had to forfeit. I finally made it to Kyoto with 10 turns left, and missing 7 provinces. I had three full stacks and had to gamble: it was take Kyoto and POSSIBLE expand elsewhere, or lose, as my strength would go down with other provinces I conquered.
I attacked, and was wiped-out. Reloaded, tried agian, same thing. Reloaded, did auto-resolve, same thing.

Fact is I just take too long getting to Kyoto, at least as Shimazu or Date. Those extra 5 years really don't help me at all lol.
What am I doing wrong? Why am I so slow? I don't get it. I mean, I NEVER pass a single season without attacking someone or marshalling a decent army/re-enforcements. So I mean, I'm not being passive by any means. I've always got my ninja out in the field, etc etc...

Any suggestions or help on speeding-up my game would be much appreciated!

How many armies do you have and what's their composition?

Also from my experience do not relay on allies who border you, they might help at the beginning, but in the end you will have a nasty neighbour stretching your front...
Having a continuous territory is the key, as you get closer and closer to Kyoto your front gets smaller...

Welll...About 30 turns ago I was planning to betray Uesugi and take my chances. Then Ikko Ikki declared war on me and killed my Daimyo. So...lol. That didn't work out according to plan. Now I'm praying they won't betray me at RD (175+ friendship level, plus marriage).

I have three armies only. Had five but two were wiped-out by the Hattori (well, one retreated to a castle, that was then seiged by Ikko rebels. Bastards. lol

Army 1. Led by my current Daimyo (previous heir). He's level 4. Army is composed of: A.4 units of Naginata Samurai, all level 3 with armor bonuses, B.4 units of Bow Ashigaru, all elite with damage bonuses, C. 2 units of Bow Samurai, both level 3 with armor bonuses, D. 4 units of Katana Samurai, all elite, with attack bonuses, E. 2 units of Date No-Dachi Samurai, elite, with attack bonuses, and F. 3 units of Yari Ashigaru, all elite, with armor bonuses.

Army 2. Led by my general (adopted heir). Level 5. Army is heavily damaged after battle with the Hattori, but WOULD be composed of: A.2 units Naginata samurai, veteran, with armor bonuses, B.3 units of Bow Samurai, veteran, with attack bonuses, C.3 units of Yari Samurai, veteran, with morale bonuses, D.4 units Yari Ashigaru, elite, with armor bonuses, E.5 units Bow Ashigaru, elite, armor bonuses, F.2 units Date No-Dachi Samurai, veteran, armor bonuses.

Army 3. Led by my Daimyo's son, level 3. Currently en-route via ship to the main battle provinces. Army is composed of: A.5 units Bow Samurai, veteran, morale bonuses (only option in the nearby provinces), B. 3 units bow Ashigaru, veteran, morale bonuses, C.3 units Yari Ashigaru, veteran, armor bonuses, D.4 units Katana Samurai, veteran, armor bonuses, E.3 units Yari Samurai, veteran, armor bonuses.

Part of the problem is I don't have enough resources to supply many more armies. Despite having 2 trade nodes, 5 trading partners, and all my farms except one upgraded to within 1 level of 'fully upgraded', and having a pretty good income, my armies take up huge amounts of supply. Uesugi takes FOREVER to get around, hence why I'm trying by boat this time. I have 2 fully upgraded Ninja on the field, but they're swarmed by 3 Hattori ninja ever turn (they survive, but it's annoying and worrisome).

Disband all naginata samurai, keep for each army around 2-3 katana/no-dachi (whichever is easier to supply near the front), yumi are fine, but make up for the naginata with yari ashigaru...
They are very cheap and spearwall does wonders :)

I'd say at least five armies, if you can afford more the better...
Exactly which provinces do you have that border the Ikko?
'Cos one solution could be to retreat from there, leaving the Uesugi to deal with them, worst case they both deplete their armies and you can take over...
Dunno if you are playing a short or long campaign, if short go for it on the Hattori front, hoping the Uesugi won't betray; if you are playing a long campaign, retreat to a stonewalled fort or build one and attack the Uesugi...

Not to question you, I AM new to the game and I realize that...but why disband the naginata guys? I thought they were really good?

Hmm. I can monetarily afford to make more, but time-wise I dont think I'll have enough time to do so. but Ill try.

Ah, i don't remember the names. I'm at work and have a bad memory with provines names. I have the three coastal provinces to the east of their capital...Echizen and three others. I just captured the one to the west of Echizen, and have a small army (maybe 5 units) seiging an undefended Hattori castle in the province west of that.

The Ikko are basically wiped-out but they hold that one little peninsula province on the coast like, 3 spaces east of Echizen. And I can't afford to move enough troops back to destroy them, so I'm forced to content myself with bottling them in with well-defended border provinces.

The Hattori control all of central Japan...basically the only things they DON'T have are Kyoto and about 6 provinces west of central honshu, currently controlled by the Shimazu. Basically all the other clans only have one or two provinces: it's down to Shimazu, me (Date), Hattori, and Uesugi. And friggin Kyoto.

They are good, but far too costy at that stage...
Ashigaru replenish very fast, in campaign they are the best troops imo, you can sustain heavy casualties and be ready to fight again the very next turn with a decent general...
If you can manage to push towards Noto and capture it, that would be very good, just beware the religious unrest...
Once that's done go all out against the Hattori with your new armies, keep an eye on the Uesugi though...

Well, last night I took your advice!

It worked. Sorta. Uesugi suddenly came-up with two more full stacks from nowhere and pushed the Hattori stack out of my tail province. What's the one directly east of Kyoto? It went back and forth there for a while. Meanwhile, the units I'd been sending towards Noto promoted one of their own as a general, which allowed me to recapture the province, barely hold-off an Ikko assault, and destroy the Ikko Ikki. Thank God. Sheesh.

Next turn I was able to set-up my main stack and the remnants of the second near Kyoto. For some reason the shogunate's second stack had been steadily disappearing (?!) but whatever. I attacked, letting the computer do the battle this time (since I sucked terribly at it last time) and crushed them.
Long story short, despite another small Hattori attack, Uesugi kept them off my back long enough for me to secure the shogunate.
Problem is now I'm in a pickle. I have 12 turns left, and I only need 4 more provinces to win. But...Uesugi just declared war on me and is marching to Kyoto from the east with two full stacks, to my one full stack of defenders. I also have half a stack in...the province directly north of Kyoto, and half in the one directly west. I WOULD pull them back to stop Uesugi, but the Chosokabe, who inexplicably hate my guts (and have since the start of the campaign) are sending a full stack through that mountain pass west of Kyoto.
Meanwhile I have two half-stacks down in Hitachi and...the province directly north of it. I've managed to capture five undefended Uesugi provinces down there, but my advance has slowed thanks to rebellious subjects.

Assemble all you can in the Kanto or maybe in the Echizen-Noto area and be the shadow of the approaching Uesugi, they should leave the provinces behind them quite undefended...
Grasp what you can in the Kinai or wherever, usually Kyoto can be left unguarded (due to its settlement bonuses), I think you can manage to halt the Chosokabe at Harima, merging your half stacks, while gathering all you can to stop the Uesugi, if possible at your best castle in the vicinity...
It will have to be a rush for the victory conditions :P

Thanks dude! I'll try it this afternoon.

I can probably stop the Chosokabe. I'll fight the battle myself...in pitched battle I have a much better success rate than the AI, likely because it doesnt use as complex tactics as I do in 'calculating' the win. Not to boast, or anything... ;-)

The Uesugi will be a problem. I can easily take on one stack, but there's no way my guys up in Echizen will be able to make it south in time to support my Daimyo, and the Uesugi keep leaving their second stack JUST close enough to support, but JUST far enough away that I can't reach it. Urg.

Oh I didn't mean to come and help against the Uesugi, but to capture the undefended provinces they left behind while marching :D
Btw if one of those stacks happen to be without a general, I'd say to go for it, there is limited amount of men on the battlefield and armies without a general are so prone to mass rout :P

Also, where are your ninja? Sabotaging one of the armies and picking off the other should do the trick.

One ninja is busy helping-out my invaders in hitachi. He'll never get there in time.

My metsuke is only level 2 (they killed my high-level one) so he's useless.

My other ninja is there, but he can only do one action per turn, and it costs more than I make to sabotage the main Uesugi stacks. But I am trying.