another place close by to TGO, just 1 exit north on I-95
http://www.seasonsinthesunrvresort.com/
I believe this one is just down the street from the one listed above.
http://willowlakes.com/index.cfm
I have not been in either of these two places, so I can not really make a recommendation. Jetty Park that Joe mentioned is nice if you like the ocean and beach, but it is 30 minutes from TGO. BUT it would be a GREAT place to watch the launch from. Getting a reservation there might be tough.
I know a few people who rent out rv pads here at TGO, I will ask around for any that might be availble.