I think it's unlikely you'll sell three boats in one swoop, given the range of personal requirements and preferences among the hardshell crowd. A Facebook group is probably your best bet for listing your stuff, like these:
Inland Sea Kayakers Inland Seas, Kayaking the Great LakesNow, let's talk about what's really important. WIH aren't you thinking of a folding boat? I paddle Gitche Gumee with my achin', creakin' 69-year-old knees in a Folbot Greenland II:
You could even hold onto that desalination rig:
The Kayak