here's how I did it. I removed both beds and just about everything else on the street side. Replaced the street side with drawers, cabinets, and a desk.
On the curb side, I cut the tub short by about 12", then put in a wall with a plastic veneer (available at Home Depot) glued on with silicon. Tub is sealed to the wall with more silicon--not the most beautiful, but in 3 years of living in it the seal never failed (surprised myself here!). The short tub allowed me to have a lot more countertop space in the kichen, but turning the sink sideways added quit a bit, too.
The bed is 48" wide. Note the small 45 degree chamfer at the foot to keep one from dislocating their knee if they miss the passageway by a little bit. There is a removable panel under the mattress that allows access to the area under the bed adjacent to the wall. The area adjacent to the passageway is accessed via three velcro-retained doors with 18x22 plastic boxes to replace the previous metal drawers--hold a lot more and seem cleaner and stronger, not to mention they have lids.