In the late 1980's and early 1990's when I went through Vegas on chip runs I'd stay at the Circus Circus parking garage. My pickup had an in line camper shell with a quite comfortable sleeping setup inside. If you park at the northwest corner of the fifth level, near the casino entrance door, there's a bathroom just inside. And a coffee shop just around the corner on the same floor...all the comforts of home. Good luck.