Hey Bleeding Shiner, sorry to hear you are getting out of fishing from a boat on a regular basis. I have a bad boat jones so I tend to buy and sell quite a bit. I have had really good luck selling boats on Craigslist. I live in the Joplin area so I aways post them in both Joplin and Springfield.
The real keys to Craigslist success are as follows: 1) Be very descriptive about all of the options the boat has. 2) Be brutally honest in your description about ANY flaws that it has - when someone comes to look at it, make sure to show them the flaws. 3)Post lots of photos. Craigslist allows you to post 4, but I always upload as many as 40 more to a public web site like Photobucket.com or Picasaweb.com (both are free). You will need to take digital photos in a fairly low quality setting (i.e. no more than 2 mega pixels) as you will have difficulty uploading them. 4) Either take the time to clean the boat up yourself or pay someone to do it for you. A clean boat always sells better. 5)If there is anything that is not working properly, you'll need to weigh the cost to get it fixed vs. how much less you will have to sell it for. Clearly, you will get the most money for boats that are clean, have newer batteries and tires and on which everything works.
One final thought, this is the time of year where you will get the most for your boat so don't be afraid to ask on the high side of what it's worth.
I wish you the best of luck!