I'm in Utah, four corners, area looking to go out for a weekend. I know of the sand dunes and "little Moab" are there any more fun or beautiful places for a weekend camping trip?
I would look at going to the Valley of the Gods. It is just north of Monument Valley and in my opinion nicer and prettier than Monument Valley. It is all BLM land and camping is free.
La Plata canyon is another place to camp if you like pine trees and cool air. I am assuming you are taking your Jeep. There is one road to the west that will take you up to 9000+ feet with a off shoot to the left and you will have your own private camping area.