Hi there~
Haven't read other posts yet, but just wanted to throw out our experience. We have a spirited 33 month old whose sleep had become an issue a couple months ago. He started carrying on and fooling around at bedtime for close to 2 hours (and he shares a room with 2 older brothers, so it was quite disruptive) and he was waking an hour earlier than our normal wake time. I experimented with his naps and ended up cutting them out. Now we have a mandatory quiet time in our house from 1pm-2pm. All the boys go lay in their beds quietly, with the light on, and play with quiet toys, read books or play with their leapsters. Sometimes, he will fall asleep and take a nap, but that is purely his decision. The bedtimes got better and he has recently started extending the mornings back to normal. I remember doing something similar with my oldest ds when he was about 3...I thought he was dropping his naps, so I just made him go have a quiet time in his room. During those quiet times, he started falling asleep more and more often until he was consistently taking naps again. I'm hoping that's what's going to happen with our littlest guy now.
As for when they go to bed and when they wake up: in addition to cutting out naps, we pushed bedtime back by about 30 minutes. Now they are all in bed by 8 with the goal of all them being asleep by 8:30. Generally the older two are asleep by 8:30, but sometimes our 2.5 year old will stay awake until 9. Everyone gets up between 7:30 and 8am.
I'm not sure what issues you've been having, but in addition to trying to tweak your lo's routine, I also recommend just riding out the problems. Sometimes these things work themselves out if you are consistent and patient.
HTH!