Not sure how much K-Mod changes things, but on regular BTS monarch/epic you could aim for:
3 cities, 2 workers by T75
5 cities, 3 workers by T110
8 cities, 5 workers by T150
I'd consider these bare minimums. With a good starting area or expansion-oriented traits (EXP, IMP, CRE), you should do much better (more cities/workers, or also working in wonders while meeting the same levels of expansion). Of course on higher difficulties land may run out before T150. If your worker micromanagement isn't great, try to have an extra worker at each of these checkpoints.
If you've expanded at this rate and are anywhere close to construction at T150, you should be able to annihilate the monarch AI with Catapult + X (elephants if you have them, axes & swords if not). Even on K-Mod. That being said, every map warrants its own considerations. Sometimes, building wonders like the GLH or Pyramids, or doing a pre-construction rush is warranted. But if you are simply interested in moving up a difficulty level or two, you can ignore those other options and play fast expansion and construction rush games.