Hi Becca,
I'm sorry I forgot to write the prices. Here' the deal with regard to tubing. You rent the tubes from any number of venders, basic tube that holds up to 250 lbs is $5. for the day. The cost to enter the park is $5. per person. If you have the Florida State Park pass you don't have to pay for the park fee. There is an air hose to inflate your tubes or small boats, I didn't see a fee. They will hold your keys for a buck.
As for bringing a water bottle with you, that's a no. I tried, we had to put them back in the car. Seriously, I didn't need a drink. The river water was so refreshing. I imagine it is clear enough to drink but...I didn't try it.
There is a campground very close to the North entrance to the park I didn't check it out but they are online, I've found them before. The time frame from O'Leno to Ichetucknee was 20 minutes about 12 miles.
Ask me any other questions and I'll answer what I can.
Lynn