Today, after having been to Lowes to get bits to plumb in my bath, I went underneath the bus with a tape measure. The blasted drain hole is precisely where a chassis member is situated. There are several ways around this.
1. Toss the blasted bath out of the back door and install a real shower as was the original plan before I went cheapass.
2. Turn the bath around. The bath is unidirectional so it would have to be on the other side of the bus, where the kitchen is currently situated. This would entail more PVC planks for the floor and extra expense.
3. Raise the bath about six inches in order to accommodate more convenient plumbing. This would make existing headroom even more restricted which is unacceptable.
4. Move the bath forward toward the front by about six inches, reducing the dinette to a single seat affair.
5. Move the bath back toward the rear. This would be a problem because of the wheel arch.
The bath is already 60 inches and the space for two windows is 56 inches so already its a problem needing extra carpentry. I regret the work I put in trying to make the damned thing fit. That's without cost of the materials wasted so far trying to make it work.
So far, nothing the hillbillies installed in the bus has been remotely usable. Their electrics were terrible and had to be ripped out. Their metalwork was appalling and couldn't be recycled. The replacement fan belt they left in the bus was the wrong size. The replacement fan was the wrong kind. The replacement horn I have not tried as the existing one works.
There seem three ways forward from this mess.
1. Toss the bath away (its bent anyway) and build a shower.
2. Concentrate on completing the bedroom area.
3. Pay for a proper shower.