Hi @AmyRoseF - Thanks for reaching out!
A conversation titled What is your camping vehicle? came up recently that might have just the recommendations you are looking for!
Personally, I had a Jeep Grand Cherokee for more than a decade that was a great car for sleeping in, leaving at trailheads, and being in town too. In the last couple of years I switched to a Toyota Rav4. At 5' 10", I have to go a bit diagonal to sleep comfortably in the back of it, but the gas milage being so much better makes up for it.
Hopefully this helps!