You can have a real shower in a van without giving up a permanent wet room. There are three approaches here and they suit very different layouts.

Folding showers deploy in the aisle when you need them and fold flat against the wall when you do not - the magnetic zipped curtain seals to the frame so water stays in the tray. In-floor stainless shower pans are the built-in option: a welded pan set into the subfloor with a drain, invisible under a floor panel until you lift it. Outdoor shower ports are the lightest answer of all - a stainless RV and marine flush port on the exterior wall for a hose and a wand, ideal for rinsing boards, dogs and feet.

All three want hot water: see Van Water Heaters. Plan grey-water capacity in Van Water Tanks, and seal the floor properly with van flooring.