Highly recommended if you have the time. Take the kids, or don't, spend a day and have a blast.
It's the Suwannee River. Like the Mississipi River of FL, except it's not as big and isn't in Mississippi.
Not exactly close to the venue but it's on the way if you're coming from the east. Daniel proposed to Julia under the big Oak Tree by the lake here. If you have the time, it's definitely worth stopping to look at. It will only cost you about $6 and it's no more than a 5 minute detour, not including the time you'll spend in awe of its beauty