...but with work/ kids dont get nearly as much time as i'd like to play it... Consequently I have selected Warlord difficulty as I don't want to have to try too hard!
I hear ya, bro. I'm a nursing student working full-time and try to keep my love-life interesting (or at least prevent stalkers, restraining orders, etc.), but I still needs to get my gaming on! A better compensation for reducing the time needed to finish a game is reducing the map size; this works much better than lowering the difficulty level. If you lower the difficulty level, you'll likely just quit all games prematurely because you'll put yourself into a position of "will win unless I intentionally sabotage myself" about 20 minutes into the game, and then spend the next 4 hours going through the motions, it becomes more of a chore than entertainment. Smaller maps means less capitals to take for domination victories, less diplomacy interruptions between turns, less computer thinking time between turns, and possibly fewer cities to micromanage.
As far as difficulty, and wanting to "not try to hard but still have challenge," we know what you mean. You want it to be fun whereas frustrating is not fun, yet you want the other players to be competent enough to be engaging. Smaller maps may help with this as either 1.)making the map smaller or 2.) increasing the game pace makes the game easier. Obviously increasing the game pace works counter to your preference.
And as Beetle said, Warlord is probably not a good place to start for anyone who has any experience with the series. Warlord (even Prince) or below is mostly just for testing theories and strategies, with Settler being that the AI will not interfere with your experiments at all, but by Warlord they engage you, but can be dismissed easily. Prince is kind of the baseline, it also prepares you for higher levels because many of the parameters remain the same for the human player from Prince all the way up to Deity (starting happiness, happiness per luxury, unit/building/research/SP cost, etc.) But I'd advise at least King, especially if you'll take my advice on smaller maps, because you said you wanted the AI to engage you and they probably wouldn't at Prince since you're experienced.
Your proposal is somewhat of a conundrum, though - you want the AI to engage with you, specifically mentioning an occasional DoW. The AI won't DoW you if it's suicide, but if it is not suicide for them, then the game inherently won't be easy enough that you won't have to try hard.