I had a bunch of external plumbing replaced on my 210 at West Service Center in Chesapeake, VA. I know what you mean when nobody wants to touch it. The obvious first problem is access to the bottom of your van. Then, if it's black tank plumbing, some people just won't do it out of fear of infection, or they're just not interested your poop. I can't say I blame them. Depending on what is broken on yours, you may be looking at dropping the driveshaft/exhaust to access the plumbing.
If you can actually access the bottom of your van via a lift or quality ramps, I say go for it. You'll learn a lot about your plumbing. Otherwise, you need a shop.
The Roadtrek dealer closest to you appears to be a little bit of a drive but might be your best bet.
https://www.google.com/maps/place/Jo...c4737edfa8dd6b
Good luck!