I've driven on the Silver Lake Sand Dunes in Michigan, which according to them, are the only sand dunes in America east of the Mississippi you can drive on.
It was an absolute blast! One of my top all-time experiences in an automobile of any kind anywhere.
One thing from the pictures - it's hard to tell, but it didn't look like your tires were deflated? Is the sand on those dunes hard enough that you don't need to deflate your tires? At Silver Lake, you can't go through much of the park at all with regularly inflated tires. Deflating is an absolute must to enjoy most of the park, unless you've got an extremely specialized set of tires.
Anyway, if any of you are off-road enthusiasts or even if you aren't, and you get a chance to drive on or ride in a vehicle being driven on sand dunes, highly recommend! It's a lot of fun!
