I live in Idaho now but grew up riding there. From the Kamas side about 9-10 miles up from the gate where you get close to trial/washington lakes there is variety of every kind of riding, you just have to get off the road and find it. Plenty of hill climbing near the top too.
From park city you could also go the noblett's side and there is some spectacular technical riding there. Not so long ago there used to be some great riding above park city and behind deer valley, but that's all on it's way to being developer/private land now, and soon Guardsmen Pass will be in the hands of developers because the Mountain Accord is idiotic. Guardsman is always great for a quick up and back ride.
We always trailered to the gate at Soapstone campground and rode up towards soapstone and lightning ridge. That area is huge and it's not uncommon even on a busy Saturday to only see one or two other groups once you get off the main road. Lightning Ridge is a fun area as is Mill Hollow. You really can't go wrong.