Tom Till, who has a gallery in Moab apparently uses Kodak E100VS. You need to stop by his gallery and check it out. Absolutely wonderful. My personal preference is for tmax 100. However, when I'm wandering te Colorado Plateau I often carry some velvia 50. Unfortunately, I don't feel I know any of te E6 films well enough to use them. Good luck. Have a great trip.
BTW: On a side note I highly recommend a visit to the castelton towers area east of Moab. It's a beautiful place and only about 30 minutes from Arches/Moab.