Re: getting a boat for free
Looking at the 1959 brochure on Fiberglassics.com for Crownline, I'd tell you if that 20HP is running - grab it.
The worst that will have to happen is that you'll have to take a chainsaw to the hull (if you try to drop it whole it there's a fee in most places), tote it to the landfill, sell the trailer (or give it away) and find something else to put the 20 HP on.
Check the decks and such like everyone is saying, but also take into account this boat is probably between 12' and 16'. To take the topsides off, flip the hull, patch, sand, etc., etc. is not a crazy project. Four guys, a couple of pizza's and a cold beer or two should have her disassembled and flipped over in a evening or half day. Definitely look through a couple of the restoration threads and see what you think. There are a couple of really nice old boats that have been brought back from the dead.