I drive a Tahoe, gas guzzler but hauls a lot of stuff comfortably.
When we car camp I wanted simplicity so I came up with a system that works really good.
I have a double size mattress that fits PERFECTLY in the back of the Tahoe. I put that in first, make up the bed with sheets and appropriate blankets. Then I slide a folding card table under the mattress. From there I pack up our gear, coolers, etc in plastic tubs and put them on top of the mattress along with folding chairs and a tailgating canopy deal. When we pull into a place to camp we back up to the view, fire pit, whatever, open the rear hatch, pull out the coolers, gear bins, chairs and tailgating tent. Set up the tail gating tent over the rear of the Tahoe, put up chairs and card table with coolers underneath and our bed is right there made up, ready to go. For ventilation I made these magnetic screen deals. I cut screen to fit my rear windows and sandwiched the edges in magnetic strips. I roll the back windows down and put these over them so air flow comes in without the bugs.
Really love this whole system, works great, very minimal cost or fuss. About 10 minutes after you back in you are sitting in your camp chair relaxing.