recycle them.. lead keels? deck hardware? standing rigging and other stainless hardware? Aluminum mast and boom.. that should cover the cost of taking to the landfill or pumping out the toxic liquids and taking it three miles out and marking it on a GPS and sinking it to attract fish..
It would be nice if recycling boat hulls and parts was lucrative enough to make it worthwhile, but the status quo would suggest otherwise. This makes sense when you consider the fact that sailing is a hobby (as opposed to a necessity), not nearly as popular as others such as automobile restoration, powerboating, golfing, etc., and used sailboats are abundant and cheap. Also, the sheer number of different boats and the attendant hardware makes finding used parts especially difficult.
I'm not sure I would feel confident using used stays or shrouds, given the potential for catastrophe should they fail.
Case in point - My marina dumped an abandoned boat that they could not sell at a recent auction in a roll-away. I cut 2 Lewmar England 25 2 Speed winches off, cleaned them up, and put them up for auction on Ebay. I got $150 total for my trouble. I'm guessing the same would be true of other boat hardware.
Recreational boats are just not all that useful for other purposes, and, as pointed in this thread, fiberglass is forever. I suppose you could turn a large sailboat into a whimsical domicile, but it would simply be more practical to find a decent used travel trailer.