I know it's not in Park City, but you ought to hear about Rattlesnake. It's a trail in the Five Mile Pass area, essentially on the border of Utah and Tooele counties. Just so you know, fellow RME member iconwill took his showroom stock 2000 Tundra ExtCab on this trail with me back in the springtime. This was on the ragged edge of what his vehicle could do without being damaged, but with careful spotting in a couple areas we managed to run the trail in both directions without a single scratch. If you're up for a little bit of a challenge, it's worth checking out.
FYI