Rental RV spot at campground/MHP Venice Fl Jan 2016

You can see them all for yourself here

We like staying at Venice RV Resort now called Camp Venice. It's in the Myakka River , great restaurant almost next door and in a very rustic area. Right off I-75, but no noise from traffic . Only downside is you have to go down a shell road to get to it . The road is very well maintained, just gets a bit dusty in dry weather.
http://www.campvenice.com/rv.html

Try searching for RV parks instead of mobile home parks. Mobile home parks generally mean permanent residents. But be prepared to be disappointed. In the winter, everyone east of the Mississippi river with an RV is already headed for sunshine. And they made reservations last summer.
I can recommend Sun N' Fun, in Sarasota near the west coast, but it isn't beachfront, and it isn't cheap, but they have 800 sites. Nothing on either coast of Florida is cheap in the winter. They have FHU pull through sites plus cable TV, and all kinds of activities. I was visiting friends that lived near there, so I didn't take advantage of all the amenities.
Here's the link.