Came across a couple photos of Ross Wooten's trip across Death Valley on a 1959 Topper. It's pretty funny that he didn't actually ride the Topper, but had someone else do it for him. Still, the Topper made a 600 mile trip in two days with no issues, even at high altitude and extreme temps.
Harley's Topper Tackles Death Valley
Harley's Topper Tackles Death Valley