Sota Diver,
Weeki Wachee is now a state park, but the only change is that there is a single admission to the "attraction" and the "water park" (I believe $29 - it used to be two separate parks). Once you are in (for the fee) you still have to pay for a lifeguard to supervise you (the lady at the front did not know the exact fee, but I assume it would be around the $20 that is has been for the past few years). It's nice, but perhaps not that nice...
There are so many springs in the Ginnie area that it is hard to beat. For camping, I like Blue Spings (Gilchrist), which is right next to the Ginnie property (and the spring is beautiful - not much depth (20'-25') but nice swim-thru's and a fun jumping platform). Huge camping area, never crowded and quiet at night (unlike Ginnie). There is also a state campground down the road (Blue Springs - Lafayette Co.) that is less expensive, but not as nice and you have to carry your gear a short distance from the parking area. There is also The Rendezvous at Convict Spring (fka Jim Hollis) on the Suwannee River. It is inexpensive and they have a half dozen or so sites that sit on a high bank directly over the river. Very scenic.
If the Suwannee River springs (and there are many) are closed/not diveable due to the flooding, there are the Sante Fe springs (Blue, Ginnie group, others) and Itchetucknee Springs, which should not be effected. The Itchetucknee River will give you a good river tube-float and Blue Hole springs there is one of my favorites. All of these are within 30-45 minutes of the campsites mentioned above.
Let me know what area you ultimately decide, and I can describe some of the springs so that you can figure out what works best for you.
Thanks,
Scott
p.s. Devil's Den allows solo "snorkelers" but don't advertise that you are freediving. Must be scuba for Blue Grotto.