Chatt, make sure your maps are up to date with the latest maps before you come down. I know that Garmin and a few of the other manufactures get their maps from NavTeq. I have a Nuvi 750 and the 2009 maps and they do not include some of the newer areas of TV. I believe the 2010 version are out but I will have to check.
I don't think Hadley, Hemingway and St. Charles area covered in the 2009 maps.
As far as sales reps, yes you can change reps. Do a search on sales reps as there was recently a lengthy thread about that subject.
I believe the sales reps of TV will only deal with property that is listed with TV and will not do anything with homes listed by other companies. A name that is mentioned here a lot is Lyle Grant for those listings. Here is a link to his web site.
http://www.lylesellsfla.com/client_services.shtml