Try
www.milfordleedy.com for the MLS list. I believe it is pretty complete.
Of course, The Villages website has all their re-sales, but they only show select new homes as representative of a model and area.
As far as FSBO's, there aren't a lot of good sites out there, BUT, when I was house hunting I just took a few hours and drove the streets of the areas I was interested in and looked for "For Sale" signs. NOTE: Some neighborhoods do not permit oputsidde signs so you have to watch the windows in the house for a sign.
Above all, look at a lot of places. I looked at about 30 before the "cream started to rise to the top" so to speak. After you've seen a bunch you'll see what I mean. I allowed 5 days for my preliminary trip to sort things out, then my wife came back with me a month later for the final viewings and purchase. Worked out just fine and we got what we wanted!