By page 4... the RV has been traded and the ending is happy.
What the car dealer paid for his trade offer is irrelevant. What the RV owner paid for the unit and improvements is irrelevant
for the purpose of making this deal to the satisfaction of the parties involved.
Is the deal lopsided? Possibly, but unless the table is flashing "TILT", both parties seem satisfied with what they let go of, and what they acquired. There's probably a Ferengi Rule of Acquistion involved...
The OP saved a bunch of time and money not administering a private sale, got refunds on taxes and insurance, and a dealer bling package for the new vehicles. Gotta have the OnStar!
The real art of a deal is for both parties to walk away getting what they wanted.