NADA pricing also works from the assumption that the rv's condition has aged and doesn't take into account the upgrades done by the owner, such as appliance replacement. They have no way, when you plug in your data, to account for new or upgraded elements and assume that all the basic components are OEM, possibly at the end of their service life.
We got our Sonoma at year end pricing, and, like buying a car at the end of a month when a dealer is trying to make his quota and control flooring costs, it came out a little better for us.
Perhaps the best way to test the secondhand trailer market is to do a test ad with your dream price. If you sell it, fantastic. If not, wait a few weeks, then put it in at a lower price and see what the interest is. Always ask more than you're willing to take and be willing to negotiate without being insulted when someone gives you a low ball offer. Simply thank them and say you would be willing to go to $x, still leaving some wiggle room. If the person is interested s/he'll counter. If not, then move on to another buyer. That is going to give you the best sense of the market into which you are trying to sell your trailer.
The bad news is that Craigslist is now charging $5 for posting rv ads. But at least it gets rid of some of the clutter.