I'm in the middle of a interior remodel. We have been on a few trips and found out what works and what doesn't.
Our biggest complaint was the bed was too high and the water tank kept freezing and it was too small. Also, the underbed storage was impossible to use when you wanted something all the way in the back.
What we're changing:
Lower the bed, and have full length pull out drawers like trucks have.
Larger water tank with tank heater.
Redesign the sink/fridge area.
Add overhead storage full length on driver side.
First thing I wanted to do was switch to PEX.
Water tank in place with tank heater:
I put the water pump between the diesel heater and water tank. The pump has a tee so that the water goes to the sink and the rear spigot for the outdoor shower.
On the passenger side, the rear spigot is recessed to clear the rear door. Everything will be painted. I'm also adding a water fill to the outside of the van.
Driver's side. Originally, the RV style power center was located here. It will be moved forward of the bed.