I'll second Tropical Palms... it's nice and big. Anything around here will be busy that time of the year so it's good that you have a head start. Lake Louisa SP is nice, but it's a drive from St. Cloud. There are a couple of campgrounds right on the chain of lakes down in that area. Boggy Creek Resort & RV Park looks really nice and seems to have very reasonable rates, but I haven't been so I can't vouch for it. I just like the location and the list of amenities. There are couple other waterfront properties nearby, Lake Toho Resort and Southport Park Campground.
--Vic, Clermont, FL
2013 Dodge Grand Caravan SXT w/ e2
2014 Coachman Viking 17BH
Nights Out YTD - 17 (6 Trips)
Travel Companions - DW, DS (5) & DS (1)