Hi, we'll since we presently live on a houseboat now, you'll find the easiest way is to actually go down to the marina's that would be of interest to you.
This way you can get a feel fo the "ambiance" at the marina, and get a look at the Houseboats that are for sale. Some of the BEST DEALS are not advertised, and there is a wealth of information from speaking directly with boating neighbors.
Hope this helps, and feel free to look at the website below for more answers.
http://www.all-about-houseboats.com
