The solution is obvious - put a piece of plywood over the dinette where your wife sleeps, supported by the side rails. You then can slide across it to the far side of her bed, before going down some steps to get to the bathroom.
During the day, the board/plywood would be under your mattress.
Hmmm. She wouldn't mind having only 16" or so to sleep in, would she? Similar to the Navy and their bunks. (all tongue-in-cheek)