Some major considerations for value:
Is it running?
Is it registered?
Will it pass any required smog or safety inspections?
If the answers to those three questions is yes, then you might find somebody who wants a project RV and is able to do the work if you price it cheap enough. If there has been water intrusion for a decade, it likely means that the interior walls and the subflooring have dry rot, too, and the interior will need to be ripped out so those things can be replaced. Basically building a new interior within the original shell.
If it were mine I'd put it on Craigslist really cheap and make it somebody else's problem. Craigslist is also a good place to determine relative value and see what, for instance $40,000 will buy you.