The use of PG2 gave me a similar feel to CC2's campaign, with the added advantage of not being linear. Now, the basics:
Using a PG editor, you can change the values of any of the units in the game. The main changes were to put movement values to just a few types, like infantry, armor, etc. Supplies and the like are organized along similar lines.
We changed the time scale somewhat for the battles, with each battle being 30 turns. Each combat was fought on a map made to resemble the terrain from PG2. Size would vary, usually using larger maps to give more room to manuever.