If you don't really have the time, the many required DIY skills, work space, tools and skilled help available, consider just selling the rig as a "project", you may be time and money ahead that way. It could take many months and lots of money including parts and labor for repairs and upgrades that you can't do yourself.
In the end, will you have something that is worth the time and money spent? Will you feel stuck with the rig and need to keep it to get some of the money's invested out of it?
We spent $13K to buy an old but nice looking orphan Class C and spent $8K more in repairs and replacements the first year, never really got it renovated but did get some touring and camping use out of it.