How many miles on your Ridgeline? As a former Ridgeline owner, I say if it has more than 5k miles, get the brake controller installed, hook it up and bring it home without worrying. You aren't voiding the warranty. Just take it easy. Your ridgeline will be fine.
For me, I was using 90% of low nada retail as a good indicator of private party value. Let's face it, not many people are in the market for such an expensive small trailer. Most people getting something that size are looking for something a lot less than the msrp on that rig. You may have a hard time negotiating on that one because the owner paid the high price without anything down and has hardly payed off any of the premium in one year. If so, he will soon find out he will have to pay in to get rid of it. If you opt to go new, there is usually a 20-30% mark up on new rvs. If you can find a wholesaler of that brand, get some quotes for a reference.
