I'd suggest doing it the other way, where everything is shown initially with the option of refine search to each area, build, type etc. I think that might be easier than having each area then refining it to all boats.
Looking good though. You'll need the big hitters onboard to make it go nationwide but as a starting point having it as leisure only will get you a good footing in the marketplace o progress from
Peter @ Boatsandoutboards4sale ~
askboatsandoutboards4sale@sky.com ~ 07930 421007