You know the price difference (if you are willing to drive) between the 3 and 5 seat models new is pretty slim anymore. To the right buyer, a 3 seat may be just as valuable as the 5- especially on the used market. @OnTheJob is right, you dont see a TON of used ones for sale around here.
I was on a pretty clean 2017 5 seater east of Columbus, Ohio in similar condition (no snorkel) and he was willing to part with it for 12,500. But I would say its really more about who is looking at the time and what the dealerships around you are willing to part with one for.
You might call around to the 2-3 closest dealers and just price a leftover 17-18 3-seater with power steering. Knock 1000 dollars off, and expect someone to want to haggle another 500-1000 bucks from there? Thats typically my strategy when selling a gently used bike.
Seems like prices are soo regional. You are close enough to Abernathy's that a guy that will drive for one is going to want to kill ya on it- to me that's not your buyer. I would also say spring market is just around the corner- dont get too eager to drop the price if it doesn't sell right away.
Good Luck!