Unfortunately there is no real good way to play the AI in a large campaign.
It seems to work best in smaller scenarios.
GMT makes a game called Roads to Leningrad. It uses a very interesting activation sequence based on drawing chits. Allowing the AI a double move is a great idea, except in games that are time sensitive (like Minsk) where the attacker needs to press on at all costs, so halving the number of attack turns will cause you lose; and if you do win it means that the AI really does not function well. Which games do you play like this?
The best way to play 24/7 is to increase your number of PBEM opponents.
Marquo