My suggestion (and this may sound odd but I will explain) is a large map with all AIs on ridiculous difficulty. Ridiculous AIs get a lot of resources around their cities so you can take over a few of them. You want lots of AIs because then you can be on friendly terms with a few of them so the game won't end if one sovereign suicides itself on you, just don't alliances. Also if you can manage to be friendly with your bordering factions you don't have to worry much about attacks since they provide a buffer, unless you want wars. Large maps are best (I think) because there's lots of wandering monsters you can level up on if you don't want to pick on AIs.
The only downside is that large maps are more prone to out of memory errors, so perhaps a medium map would be better, hard to say since some people seem to be able to play to turn 500+ and I can barely get past 250 (haven't played with 1.09e yet).
This is the set up I used when I wanted to do the same thing. A little bit of city spamming (I controlled 1/3 of the map) and I had pretty much everything by turn 250. I played 250-300 but was just researching whatever because there was nothing left I wanted to experiment with.
Edit: just read the interim posts a bit more thoroughly and noticed you mentioned the normal difficulty being your real opponent. In this case ridiculous may not be the best setting for you. But there's 2 things to consider:
1) More AIs = more resources on the map because of starting location resource seeds, and
2) Higher difficulty AIs = more resources on the map because as difficulty increases they get more resources seeded near them. Ridiculous setting it's not uncommon for them to have 6+ resources connected to their first city.