One thought is that the RV came from Las Vegas, not Colorado, not Northern California--some places are just better to find a used RV than others. The market is more active, the owners less likely to be underwater.
El Monte can find RV's in other areas of the country, as well as Cruise America. You might pay a premium for the service of maintenance records and for higher mileage, but you have a reasonable expectation that you can get a few years out of the machine without major expenses--if you know to ask for batteries, tires, etc.
On the other hand, dealers do seem to think all their customers are rich and will pay over book prices with fees for delivery etc. thrown in. I don't know what to do about that. Car dealers are difficult too. I guess we can just be glad we don't have to buy everyday items like we have to buy cars--we would never get out of the grocery store.
There is a lot to be said for a sales staff that meets their promises, gives attention after the sale, and does not find reasons to charge extra before the deal is signed. Glad to hear such staff do exist somewhere.