vehicle-layout. For simplicity sake I’ll reference mostly my own experince and build with my current car . However, given the infinite vehicles, lifestyles, purposes and people, animals involved I’d mostly reccomend you to YouTube content that matches your interests.
What I can speak to is Subaru and mini van camping. My gf and I first started attempting this out of my Subaru outbsck, with a small battery, not much room for storwge, no room inside the car to move around at a 6 foot length behind the front seats to the rear. The minivan was a game changer for camping and layout. With almost a 10 foot length behind the front seats, we had space for a larger bed and a couple feet or room for our dog Lula to sleep also. If it was just me, a van would be an increasingly large space and more then enough room to bring enough provisions for 2 weeks or more.
The fist things done on the van was to remove the rear seats and seat belts along with the center console for easier passthrough. I then did a raised platform about 4 inches higher using 3\4 inch osb with smaller 2x4 pieces under to support in the center and edges. We used a pattern to cut the sides of the wooden platform so that we had little to no gap between the door and floor. Once we had our unified surface it was layered with an industrial type carpet you can find for very cheap at Home Depot. It is water and stain resistant and very easy to lay down with double sided carpet tape, and staples around the edge, again providing a seemless look from the floor to walls.
The sienna has a deeper storwge in the rear trunk about 2 foot deep 2 foot tall and 4 foot wide. I choose this spot for the battery, especially due to size and not wanting people to ever see it looking inside the car. It also was more protected from the elements and if any water or liquid was spilled. The bed was positioned directly ontop of where the battery went, with enough space on the sides for smaller plastic storage bins.