I decided to take it easy and visit a local state park, Wekiwa Springs. I read that canoe rentals are available and I planned to do that.
However, I got a late start and arrived at the park mid-afternoon. After walking around for a few minutes, I found the swimming area, sat on a bench and read a book instead (The Secret Life of Bees). I watched people snorkeling and floating around, and enjoying this area that had a "summer swimmin' hole" feel. Perhaps next weekend I'll come back, after my things are delivered - I'll have my swim trunks so I can jump in, and my bike so I can take a leisurly ride along the trails.
I parked under a huge shady tree, covered in moss.
The canoe map shows several points of interest, including a waterall. This area isn't completely flat ;) but I can't imagine that the waterall is very tall. However, the suggested round-trip times were higher than I expected, due to the current. I'll have to come back and rent the canoe another time when I can get to the park earlier.