Welcome bigmike to the MOC Family.
Here are 5 links to campgrounds in the Sarasota/Bradenton Area. Although we have not stayed in any of these parks we did a drive thru in each one and placed them on our list of future stops.
Sun-N-Fun
Encore RV Resort Sarasota-North
Terra Ceia Village Resort
Fiesta Grove RV Resort
Frog Creek Campground & RV Park
And here are links to
FLAUSA-Sarasota/Bradenton Area and
See Sarasota for other area campgrounds.
I should point out that January thru pretty much the entire month of March is the SnowBird season down here and you may have problems finding anything available for the 2 months you are seeking.