Find a place to park it to work on it, if you can't work or store it at your residence and insurance first. Some very good threads on the trials and tribulations from the members here on the various insurance carriers.
Once that's done, Publicsurplus.com
are some of the best sites to search for your bus. Fleabay and CL require watching and being able to read between the lines.
Stay away from northeastern, Rust Belt, or coastal county buses- mainly because of corrosion. Look into the interior, South and Northwest and Pac Coast areas.