A week ago, I flew to Las Vegas for work and rented an R1200GS with well-used Tourances from Las Vegas BMW and rode to Death Valley for two days of riding. I met a friend at Stovepipe Wells on his TKC-clad R1200GS. We covered about about 100 miles of gravel including a ride to "Racetrack" and the "West" road that parallels along Bad Water.
The views and riding were outstanding. On the rental bike, I was a little nervous in some of the sand and had to be helped through a gulley but it was otherwise fine. For a noob, I think a KTM 640 or KLR 650 would be perfect. Or a 12GS with good tires.
(A lot of those images look familiar and I apparently missed some cool stuff too).
By the way, I will return to Las Vegas BMW. The staff were great, the pricing was fair, and the pretty blonde behind the counter smiled at my ugly mug.