Jannette, there should be an off switch on your ceiling lights so that the interior lights don't come on at all when the doors are opened.
Check your owners manual to locate it in your vehicle.
Vehicle tents have their advantages in that they expand the living area of the vehicle. They also have disadvantages like having to separate them from the vehicle if you want to go somewhere.
A friend had one that was free standing and you could either use it that way or open up one of the side walls and attach it with a special panel that zippered on to the tent. It was a combination of both but it took up a tremendous amount of space in her roof top cargo carrier and was a PITA to set up. It only got used if the plan was to stationary for a week or more because of the time it took to pack and unpack.
Perhaps you'd be happier with a self made one. I used to use my 10x10 free standing shape canopy for that by parking quite close to it and then using a clear side panel to drape over the roof of my mini-van. I could step out in to the shelter through the side sliding door but also close the door at night for sleeping. The 10x10 area was set up as my kitchen and living room with lawn furniture and the camp stove, etc. The mini-van became essentially my bedroom. To drive off and leave it in place all I had to do was take the side panel and unhook it from the van. No it didn't give me bug-free living in the complete complex but it sure was a whole lot easier and cheaper. That's what mosquito coils and bug spray are for...