I took my dogs to Death Valley. The first thing I did was personally confirm with the park that the time of my visit was "dog friendly" AND that I would be able to leave them in the suv safely while I visited various sites for photo ops. I went in December.
These are some of the considerations I took:
I kept a water bowl and 5 gallons of fresh water in the suv at all times and provided water regularly.
At each stop, I brought the dogs out for a walk around the parking lot for a bit of exercise and potty breaks.
I incorporated visits to dog friendly areas where I could walk the dogs along the road so they could safely take in smells.
For scenic spots where dogs were allowed and in the campground, I made sure that I followed ALL the park rules. I always picked up after the dogs, I always had them on a 6ft non-expandable leash, I never left them alone outside of the RV. I never took them on paths/trails they were not allowed to be on (it was amazing how many people ignored the "no dogs allowed" signs or feigned confusion about what a trail or path was - if it's unpaved or wooden, that's your first clue).
I got and used
these so I could safely have the windows rolled down partially. They allow more of the window to be open while keeping the dog(s) fully inside and hands safely outside. They work better on rear windows that aren't curved at the top.
I never left the dogs at the RV (the cats and bird stayed there) because: 1) if they barked while I was gone, it would bother other campers; and 2) they enjoyed car rides and being able to things even if they couldn't get out and explore. To me, leaving them in an RV all day was no better than leaving them at home.
My dogs were well-behaved in the car and I parked as far away from the crowd/trailhead/path as possible. I had many people ask me about the window guards - they really do work great.
I follow this list wherever I take my dogs. It has worked well. My dogs get to go with me and see/smell new things, and we don't upset our fellow campers/visitors while we do it.