Re: Which 27 footer to buy.
Yea, it's doable if you go in with the right expectations and are patient, the latter being the most important. You need to be willing to walk away, realizing you may not find something else for another month.
I would expect a sailable project at that price and size range. I've seen a few that wouldn't fit into that category, but most that I saw definitely were projects. Most had expensive systems (e.g. engine, sails, rig, electrical) that needed substantial overhaul or replacement, but it all "worked" for the time being. I would focus on the important stuff (mainly structural integrity) and just realize that the rest of the boat is probably going to need attention in the next year to year and a half. That's our experience, anyway.
To put this into perspective, we got our Cape Dory 27 for $4k. The boat needed the entire electrical system replaced, most hardware needed new bolts and rebedding, it needed a new engine, new paint everywhere, new cushions, new rigging, new sails, and a bunch of smaller things. With just about everything listed above, we spaced it out across a period of a year and a half, with the boat almost having everything it needs done in the next few weeks. I view it as financing without the bank, you put money into it every month to end up owning something you couldn't find or afford right from the start. The key was to make sure that the systems that needed replaced were either non-essential or good enough to last a year or two, in our case they were. We knew this going into it and knew we'd spend over double what we paid in improvements and repairs. We were able to sail the boat in the river while we worked on fixing everything.
Your best bet is to search Craigslist in a 300-400 mile radius of where you live, you can use searchtempest.com for that. When you find something you are interested in, go over it thoroughly and get an idea of what needs to be done. If you don't have experience, then take a friend that does or a surveyor, if you are really interested. Also keep in mind that $5k is towards the bottom of the price range, the closer you get to $10k and above, the easier it will be to find something and the less work you'll have to do in the long run.
I'm in FL as well and there are definitely things in your price range for sale, you just need be patient and look every day.