I don't know....
If you already have an RV in good condition, it might be a piece of junk but if you don't have anything to camp in it may be a godsend.
The pictures depict a roof that has had about as poor a sealing job as you'll find. I had a similar roof, many layers of different caulks, roofing tar, and sealing paints. I removed all the stuff either mechanically with heat gun and scraper, mechanized wire brush and, finally, chemicals and solvents to remove any trace. I then sealed everything with Eternabond tape and applied an elastomeric roof paint. I have had no further problems with the roof leaking.
I'm guessing a couple of weekends for cleaning and sealing it all back up. Solvents and Eternabond will cost around $100. Tires-they are leased, you need to put new ones on every few years.
Newly painted and sealed roof:
Before--

During--

After--
