We actually did two 4x4 tours with Navtec on consecutive dates in mid-July, one twilight 4x4 tour of Arches NP back country from 4:00-8:30pm and then a 1/2 day morning 4x4 tour of Canyonlands the following day. Both guides, Phil and Buzz, were TERRIFIC, knowledgeable, experienced, friendly, and passionate about their work and the parks.
We truly enjoyed seeing parts of the parks not otherwise accessible to the masses. The vehicles (Toyota Land Cruisers) were well designed for the terrain, much of which-especially on the Arches tour, is rugged, bumpy, and jostling. The dirt road through Canyonlands was a smooth ride. The vehicles can seat up to 4 guests, but in my opinion, the back seat is tight (shoulder-to-shoulder) for three adults. The person sitting in the middle-back misses out on some views along the way.
That being said, we stopped often, switched up seating, and enjoyed both tours very much, and highly recommend. The guides’ knowledge of history and geology, and the access to back country, are essential to getting the most out of your visit to the parks.