I've been to Moab and it was great. We camped at a BLM site right on the Colorado river, just north of town and to the east on 128. The camping is primitive, but great setting. the farther you get from town, the less occupied the campsites are.
I've only ridden part of Slick Rock, a classic of course. And I rode Porcupine rim, both were great trails. We also did a ride up to the edge of Arches National park, then you park your bike and can hike into the park itself. It was a pretty mellow ride, I think it was called Klondike trail but I'm not sure.
Fruita is also close by and if I had to chose between going to Moab or Fruita, I'd actually choose fruita. Especially if you're looking to do a little more cross country type stuff, without shuttles.
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