Plan ahead, start bulldozing over a bit before you get all the necessary techs. Your improvements should almost all be done by ~1000AD +/-200 years. If not you might want to add a few workers (they're like 2 turn builds anyway) to help out.Question:
At the times when some of you decide to "bulldoze all the farms/cottages for workshops", how many cities do you do that for? It takes a huge amount of workers to do this fast.
Do you go all workers for one city at a time or do you gradually workshop a couple of cities?
Also, is there ever a reason to workshop a hill? or is the window until railroads generally too small?
I drool too much over the random resource discovery that I always mine the hills (should probably windmill more).
Can't workshop hills. However if you meant windmill then yes... the extra food from hills means you can work more tiles and you get more production overall, requiring less farms. Especially after RP of course.
Grouping/separating workers depends. Grouping them is more efficient to get the hammers 'now' while separating them means you only need to micro every 4/6/8 turns and lose a bit less workers movement... which shouldn't change much really at this point in the game.