I finally went down the aisles in Lowe's. Sheet rock is my cheapest option compared to everything else. So the plan currently is sheet rock on the walls, Styrofoam ceiling tiles, press-and-stick tiles on the floor, and paint what needs painting.
Everything that usually lives in the back bedroom has been stacked into the living room and the hall. Luckily my house was originally built as a double-shotgun, so the four original rooms have multiple doors to the other rooms. I left myself a path through the living room to my bedroom door. Actually, the living room photos are missing one element. I first hung up the clothes I'm not wearing on the shower curtain pipe, but that lasted until I needed to shower. I borrowed a closet-on-wheels from Mom and squeezed it into the living room. The only things I left in the back bedroom was the extra mattress and box springs, which blocked the closet doorway.
The furniture I didn't want to drag too far ended up in the hallway blocking my bedroom door there, but the path is clear to the bathroom and back bedroom.
Once everything was out of the way, I took the Closetmaid shelving system down after taking plenty of pictures and measurements so I can put it back up in the same configuration. It works well in the room. The plastic-coated wire shelves went to the back porch so I can scrub the mildew off when the weather warms up enough for the job.
Remember when I said the mattress and box springs were blocking the closet doorway? The doorway is taller and Mustard climbed up them and got stuck in the closet last night. The only other way out of that closet is over the wall between it and the bathroom's closet that doesn't reach the ceiling. While there's nothing in the back bedroom closet for Mustard to hurt—I'm tearing it out to enlarge the bathroom so I never got used to using it as storage—I do store lots in the bathroom closet.
Mustard decided that my hands, the towel, and the broom were all evil enemies that must die while he had the high ground. I got him down without major blood loss and remembered I have an extra door, currently stored in one of the sheds. Went to bed planning to pull it out and use it to plug the closet doorway.
The next morning I figured out how to get everybody to leave me alone while I'm working on this project: get up early in the morning, find the door at the rear of the shed, and pull it out without taking out anything else all by myself. Trust me, I didn't want the help and the aura I put out compelled everyone to leave me alone.
The door needed scrubbing once I got it out in the sunlight. It was warm enough to not turn my hands into bleached-icicles and the mildew died. While the door dried, I trimmed the spray foam snot off the siding wall. I still need to clean off spots where it dribbled with some acetone, but that can wait for later.
I thought I'd have to hang the door but it didn't fit well enough to hang by the hinges. Propping it in the doorway blocked the top above the mattresses. WIN!