I just did white rim. You'll need at least one camping permit while you are there. Unless you basically baja the road, starting at 5am. Which defeats the purpose. If I had to do it all over again, I would've started the trail early one morning and camped at White Crack, finish the trail out on Day 2.
Or more reasonably, start mid day up at the grand view, take my time up there, then go down, camp at Airport, then 2nd day, head for candlestick or Potato Bottom campsite. Finish out 3rd day. If you do White rim, you'll need a spare 5 gal gas can. I left moab, went to the airport, then grand view, then down Shafer trail, then white rim, and out to Moab. Burned 17 gallons in my LR3. The other LR3 I was with, he did Potash road, then up Shafer, then met me at grand view, this burned about +5 gallons. I'd have the extra fuel just so you could do all the side trails, come in on Potash, etc. The grand view is A MUST if you're going to do White Rim as is all of the other crap up there. The side hikes are wonderful too. On the White Rim, the side 4x4 trails are great as well. Try to give yourself as much time as possible. We did it in a day and some change, and really, we rushed it. Looking back, I would've much rather NOT been fighting the clock. Everytime we stopped, we felt like we were wasting time. Not worth it.
White rim isn't difficult. When you hit Dirt, shift into low range, and keep the transmission in drive. Will keep the car running economically, which is what you need out there. Also between Airport and Labyrinth campsites, leave it in off-road suspension height. I didn't and got re-educated a few times. Nothing damaging, just a nice "DING" noise against...something under there.
Moab the town is a lot better setup for off roaders than Telluride, Ouray, or Silverton. They have good amenities and you can actually go relax there. Also Arches National park is AWESOME. We just went for an afternoon and saw one arch.
Oh for Moab and Ouray, if you an east coaster, try to get you some cardio in before your trip. The guys in my group who exercise vs. those who didn't was quite apparent. You gotta be tough to be out there.