Car-based builds don't need to be overthought and there are usually few layout decisions to make. This setup uses the common and efficient setup of a bed platform over storage with a rear-oriented slide-out kitchen. Extra storage is gained via roof-racks.
Drawer System I've been working on when I've been able to. Using Blum soft close slides and solid maple for the boxes themselves. Had some with "tigering" set aside for a special project and this fit the bill.
Cooler on the roof rack. Only needs ice every other day!
Coleman 2-burner grill on slide-out drawer with storage behind, and utensil drawer underneath.
Bed platform over slide-out kitchen drawers. Platform extends over folded down passenger seats also. Big enough for a trailside mattress, two people, and a small dog.