placename,

Are you suggesting visiting Death Valley in August? and camping there as well?

I fully agree with everything else you suggest.

I will also add that as much fun as camping is, and can maybe save money, it is more time consuming--and these folks may not really have the time--actually don't have it as is now planned.
With 3 of them travelling, splitting a hotel room may in the end be as easy and economical.

Yeah, but it may be easier to find campsites than hotels near these parks in August.

Also, the park and near-park accomodations are more expensive for the type of accomodation offered and you would need to research the budget.

I mention Death Valley because it is in the traditional Las Vegas-Sierras loop. There are some higher elevation campsites that are more tolerable in August, although the A/C Furnace Creek Ranch rooms are preferable. Wildrose, at 4100 ft may be ok. The two high elevation campsites (Thorndike and Mahogany Flat are 4WD access only because of the high-ground clearance and rocky access road).

Nah. Just skip Death Valley in August. It's really an ordeal. Camping at anything less than 7400 ft is going to be miserable.