Selling a Handyman Special
Well, as far as keeping or selling, that's really a personal decision. Only you can know if you want to or not. But, since you did mention that the rebuild was more than you want to get into, maybe you've already made that decision?
The big unknown is whether you'll be able to get anything for it. You might but many people aren't going to be interested in a partly gutted rv that is going to be a major project. The potential pool of buyers willing to take that on is very small and those who are interested are going to want it at salvage price. The issue is that for about 10k or less , buyers can get a road-worthy unit of the same vintage. Only a few are going to be willing to put in enough sweat-equity to make your unit road-worthy to save (maybe) a few thousand.
I hate to say it but the best option may be to have it hauled away and cut your losses. Sorry!