Sideways bed and internal flares

We reclaimed the wall depth

Instead of buying exterior fiberglass flares, we built internal flares around our two bunk windows. The recesses move the finished wall line outward only where our heads and feet need the room. That reclaimed a few valuable inches from the wall thickness and let a normal full-size mattress fit sideways across our Promaster.

We did not trim the mattress, cut corners off it, shorten it, or order a strange custom foam shape.

Could an internal recess work for you?

Before paying for exterior flares, look closely at the space around the planned sleeping height. Windows, body ribs, insulation, wall framing, and the shape of the shell all matter. Some vans can give up useful wall depth; others cannot. This is a design question, not a Promaster-wide promise.