In my KH campaign (my first EB single player campaign victory, woot) I took Crete with the army that's there on the first turn (actually I didn't expect to win, but I noticed the army only after I disbanded my fleet... ). Go Spartans. And crappy sallying AI.

Then I also disbanded everything I had on Rhodos except the family member, and the same on Crete (in retrospect, I probably would have saved a ship to evacuate the Crete army except one garrison unit, since those Spartan bodyguards need to die in glorious battle early. SOOOOOOO expensive.

I'd recruited one unit in Sparta, and just sort of sat there worried with my southern army. The key to the campaign is that even though Epirus simply refused to attack Macedon, the Makedones couldn't take Athens with its garrison. They assaulted the walls time and time again, but pantodapoi phalangitai and akontistai don't do that well going up ladders against KH generals.

After 3 or 4 failed sieges, they sent the Corinth garrison to join the next one, I took Corinth with the Spartan army, then Chalkis during a lull with my combined army, and then my campaign went nowhere for about 20 years when Halicarnassus revolted and I was intimately involved with a general brouhaha in Anatolia, virtually unable to hold a city, but investing in levies and mercenaries and benefiting from revolts, taking and trading cities with Makedon, AS, and even Pontus.

That was intensely fun (if in retrospect strategically fail) until Makedon did something stupid and wasted their armies taking Thermon. I picked up Thermon and Demetrius from the disaster, and the campaign entered the middle stages...