Salvic:
I don't know many places, but there is one easy in and easy out that's just off I-40 at exit 151. It's on the north side of I-40. It's about 12 to 15 miles west of Williams, Arizona where you can catch the old steam tourist train north to the lodge in Grand Canyon National Park. This area is open and solar friendly.
If you're heading westbound on I-40, get off at exit 151 and turn right at the stop sign. There's usually perhaps four or five RVs in there at night. Just pull up anywhere.
But be aware if you are heading eastbound on I-40 you would turn left and pass under the interstate. The vertical clearance is only 11 feet under the interstate bridge. In this case, do not exit at 151 if you can't fit under that. Continue eastbound to exit 161. Exit and turn left. Get back on I-40 westbound and come back and exit at 151.
There is an exit 157. However, there is no crossing over or under I-40. It's just get off and back on the same direction. To turn around, you must go to exit 161.
I usually overnight there when I'm heading to Pahrump, Nevada. I have friends in Las Vegas and Pahrump after living in Las Vegas for 42 years.
There is a post in another thread "Boondocking north of Flagstaff" with an interesting location off US-89 north of Flagstaff.
I'm in northern Alabama right now and don't expect to head to Nevada until July when I meet friends flying in from Australia and we're going up to the salt flats to watch the land speed trials in early August.
Dave