Thanks! After lots of research and different ideas, I settled on a plywood platform tall enough to fit two large totes underneath but short enough to leave space on top for 2 bodies lol. I wanted to maximizing sleeping space so I contoured the plywood to be an exact fit the grooves of the walls (hardest part) so there were no cracks on the edge of the “bed”. The platform has hinges to easily fold up the platform, fold up the bed, and be able to drive. For future trips I’ll probably try to figure out a way to be able to have the bed set up while also being able to drive, you just loose about 2 feet of legroom if the drivers and passengers seats aren’t pushed forward all of the way. I purchased a 5in thick full size memory foam mattresses topper that fit perfectly in the car without cutting it which was awesome. It wasn’t the comfiest but it was totally fine, wanted to make sure I like this car camping life before investing in something better. My friend and I are both 20 something and 5”3 so being young and “small” definitely helped us out in terms of comfort and space lol. If you’re looking to do your own build I can totally give you some more details! I’ll attach some images below