How do I field enough troops to stay offensive minded and yet defend taken provinces?

Carrion Woods will be hard to win with Try to establish a front and put your reanimators and making Mandragoras. Also search every site you can for Death/Nature gems so you can get enough to really start fielding some troops.

Also you should *probably* gear your research to Alteration 5 first. So you can cast Mother Oak with 20-30+ Nature Gem boost to the spell so you can start getting a regular good income of Nature gems to keep up your summoning.