Sometimes I am in my country house, no Internet, no... nothing, but RoR is with me in my portable, so, single-player it is.
My suggested settings are:
MULTIPLAYER. 150 or 200 poulation limit (there's no way on Earth where you will win against 7 computers with only 50 pop, so you need to set it up as multiplayer, to increase pop limit).
Enemies: 7 Computers, all teamed up against you.
Difficulty=Hard (hardest is stupid, because nowhere you are gonna face guys able to be Bronze with Cavs in your town at 5 minutes)
Enemies: 1x7 (make sure you place all the CP (CP=Computer Player) in the same team!... Never play less than 7 enemies - or it will be no challenge at all.
It's like Doom - if it moves and has a different color, then it's an enemy, LOL
Now about map type and size: Start with Gigantic (you will easily).
Then move on to Huge.
When you are really good, then you can try Large...
Smaller maps, the CP won't give you time for anything.
Map type: choose one where you can have enough land and enough possibility of contact - you want to fight, not to play SimCity (I guess).
Warning: The CP plays Highland and Hill Country better than you sometimes... (superior scouting with Villagers)
Make sure that the computer has competitive Civs. I normally set all them to RANDOM.
Now the fun begins.
If you set it to "Victory Standard", it will be a VERY hard game. Artifacts being stolen all the time, Wonders going up everywhere... It's demanding and fun.
Suggest that you start with Conquest (to get the hang of it).
No, it has nothing to do with Multiplayer.It is simple and pure fun and a moderate challenge.
Hints on how to set difficulty levels:
Play always on hard and always 7 CP teamed up.
For the least difficulty do Gigantic, and then increase the difficulty by diminishing map size. If you can beat the 7 CP in Medium or Small, then you are starting to be very good at this. Move on to AoK Start with Reveal, then make things harder on youself by turning out the lights...
Try to win a land map without walling and without building towers!... This is the quintessence of this kind of play...
And when you feel that you are really good - hey, try to cope with the 50 Pop limit....
I have organized 3 and 4-hour games this way, some with a lot of adrenaline flowing - reduced to a few villies and a few military, the comeback was very sweet.
However, I assure you that beating ONE Human is certainly more challenging than beating 7 computers!...