We go there twice a year to dirt bike; early May and early October.
If you can, boondock! Town is busy in the afternoon, near gridlock busy. Being a single lane on the north end of town makes it nearly impossible to get into/out of the campgrounds on the north end of town. You have to force your way in because the majority of us Utah'ns drive like jerks. Sorry for my soapbox.
We stayed at the Slickrock Campground twice. It was decent; busy (full) but a nice place. We boondock north of town a little ways down Dalton Well Rd. Accessible by 2wd, plenty of room, good views, and pretty quiet too.