Any tips for getting through a campaign faster?

[Pikenier]

I believe I am right in saying that even in glorious achievement mode you will get offered a victory if/when you've conquered 60% of the provinces.

That is true. There is no need to choose conquest mode at all.
When selecting Glorious Achievement mode you can also win by conquering 60%. And if you continue also the 100% conquest victory is included. Or just wait until the endyear 1453 - then the Glory Points decide the victor.

Oh and GA has other adavantages as well. When a factions gets destroyed and reappears later in the campaign their Glory Points have been deleted. So they have to start new from zero points. Can be of some advantage for the human player.
And the greatest advantage is that all goals are optional. You (and the AI) are not forced to fulfill all of them. As long as you have the most points at the end it doesn´t matter if e.g. all crusades failed or something like that. ;-)

edit: When selecting a late (1321) campaign then the campaign is over faster obviously.
Glory Points help also as you can hold your empire smaller and don´t need to conquer 2/3 of the map. Fewer battles = fewer hours to play.
Try always to invade with superior numbers. Cause often the AI retreats to the castle or leaves the province resulting in fewer battles also.
Never fight siege battles - wait until the garrison surrenders. Use assassins or spies to open the gates and take over the castle at night. So you don´t have to wait three or four years and have to fear the enemies bringing a relief force from nearby provinces.
Try also to kill enemy royal families either in battles or with your assassins. Maybe a high trained Inquisitor can also burn some princes. When the faction gets destroyed (=no family members left) their troops get rebells. Easier to conquer as they don´t interact anymore. You can collect the provinces one after another.