More on topic, I've used Stagman (Desolation Outfitters) on numerous occasions. I did 23 days from Flaming Gorge to Lake Powell. At the end of the first week he met us in Jensen with my rig where we offloaded garbage, took on fuel, a motor, water, and a prepared cooler he had kept frozen for us. A week later he met us at Green River State Park where he once again brought us another prepared cooler, ice, fuel, alcohol, water, and offloaded more garbage and fecal matter. He's a full service outfitter so shuttling is just part of his business. Most if his drivers I've seen are the elderly, retired and presumably on fixed incomes, never seemed to be in much of a rush.
Consider the difficulties associated with running a small, specialized business in a rural area. For Stagman that means wearing a lot of hats. It also means filling his vehicle with drivers so the maximum number of vehicles can be shuttled in a single trip. I always request my vehicle be delivered at least a day early so as to avoid any confusion about having it there on time.
If you're overly concerned about your vehicle, and you have 2-3 extra days and/or a motor, you can launch at Jensen and save the wear and tear... all paved roads from there. Just make certain you have your ducks in a row for the rangers as you're stranded at that point. It's all flat water.