First I might suggest getting a price to tent the RV and have it treated for termites.
Then ask the termite people about renting the tent for a few weeks, until you have time to deal with the roof leaks. They probably can let you use the tent for a few weeks - no additional cost or something minimal. Your storage company might not 'like it' but really they can deal with it, you are a long term customer, and probably they can handle it.
As for coating the roof, this is something that 'anybody' can do. You might be able to hire a local handyman to do this work. Look on
Craigslist.com for a handyman able to paint. They are not to afraid of heights, and can apply this stuff, easy enough. You will need a couple of dry days, it will be warm enough (must be applied over 55F).
They will need to clean the roof, using care not to push water into the leaking areas. Then paint on this coating, you will probably require about 10 gallons. Cost should be around $1,000 - give or take and that will also allow something like $200 for labor.
If you are really afraid of hiring a stranger to work for you, you might consider a labor company, like Labor Ready (that is what they use at my work to do odd jobs, such as taking out the trash in the retirement center where I work). They can send out a person who has had a background check done, and will perform all sorts of manual labor, such as cleaning the gutters of your home, or raking leaves, and such.
Check out this video, it shows how easy it is to apply the product. Do you have any children who could apply it for you, or perhaps they have friends who can do something like this? It really is as easy as applying paint, and I did this to my RV last year. It leaves behind a really nice looking roof coating, and looks like a white paint job. You probably would not have a problem selling your RV once coated, and the interior stains from any leaks are cleaned up, and painted over or treated so you can no longer see them...
http://www.epdmcoatings.com/videos_play.php?vid=25 Watch the video. Ask questions if you want on this page. Or start a new topic, about roof leaks, and someone might chime in on how they did this to their RV as well.
Good luck, and hopefully you can sell your RV and buy something that you are comfortable driving. A class C in the 24 - 26' range is very easy to drive, and they take in trades of DP's! That solves your problem with selling the old one too! It sounds like you might have to drive to a larger city to get a good deal on the next class C, and trade in the old one. Explore your options. They can come get the old RV if you are making a deal to buy the new one. But it is important to get the leaks fixed, and looking good before trading it in. Anything that the dealer does not know about ( termites and prior leaks) they can find on their own, or really do not want to know about, because anything that you do not tell them, they will not need to pass on to the next buyer.
Fred.