Newb Strat Q. - Dealing with incursions ?

[Kel]

I have a general strategy question (not about generals...maybe I should say generic ? I have seen the 'language wars' some people have had =P).

Assuming you are at war with an approximately equal force (even slightly weaker), what is the 'best' way to prevent them from just rampaging through your territories ?

I realize there will be large variations based on nation, spells available, MP/SP, etc...but I am hoping for some more generic advice, assuming it's mid/early game and *not* one of the 'specialty' races involved (Ermor, for example), how would you usually handle it ?

Splitting forces and trying to guard everything will cause nasty attrition losses against an undivided army. I have read people talking about their front lines...but unless you have a single territory chokepoint, isn't your 1/2, 1/3 or even 1/4 strength army going to cause minimal losses to a decently built full strength army ?

Trying to corner them is a guessing game that seems to take forever and, in addition to destroying PD's with no losses, rampaging armies seem to cause unrest (not surprisingly, I suppose).

PD's clearly aren't meant for dealing with main forces (nor should they be).

In some situations, assassins have worked ok for me but it's pretty situational (need to have assassins first off, need to have some ok items for them, need the enemy commander to not be too nasty).

Atm, I usually just rampage back...which works 'ok' but I end up not expanding and with a lot of 20ish level unrest. Nothing terrible but wondering if there is a better way

I haven't really tried a lot of guerilla/attrition tactics yet so that's still a possibility I am playing with.

Ah well, any advice ? Post ended up a little longer than I planned...

- Kel