On my site there are a number of things such as maps that dont get listed in other places that are designed around solo gaming. In particular I like them larger, and lots more choke points, than would be used for MP gaming.
http://www.dom3minions.com
You might consider having some fun with the allies command. Especially if you like playing with the All Ages mod.
#allies nation-number nation-number specific AI will not attack AI
So, for instance, if you wanted all 3 eras of Pangaea to not attack each other use something like notepad to add these commands to the end of a map.
#allies 11 40
#allies 40 61
#allies 61 11
You might also toss in Oceania since they are basically water versions of Pangaea. Maybe even group in other non-human nations. You can create an alliance of blood nations, nations with lots of undead, nations of man, nations of giants, etc.
Here is a list of nation numbers...
http://www.dom3minions.com/docs/nations.txt
Throwing in the semi-blank nations can be fun on a large map. They are basically weak nations which will scatter guarded castles into the game to be captured and used by you and the AIs.
In my SingleAge mod (which was before All Ages), I included lines for Special Monsters and Independents. Im not sure if it carried over to All Ages. The SpecMons can be alot of fun to toss into a solo game. They will be an AI nation, with castle and temples and labs. But they play with the white banner of the Independents. So its hard to know where they are. And suddenly you get attacked by "independents" of mixed units. Its like turning on full AI for the indepts for 2 places on the map. A very different game.
Its also fun to build super gods for SpecMons using map commands. Using Horrors as gods, or super angels, or Tarrasgue. Using Eater of the Dead is fun since it eventually "breaks free" and starts wreaking havoc across the map.