I grew up at Jax Beach so I’m familiar with that area. I’m sure its changed a lot over the years. Jax covers a huge area though. I’d contact a local bike shop and join one of their group rides. They’ll know all the best roads, etc. I ride with a neighbor and I swear he knows where every restroom is within 20 miles. I wouldn’t ride alone if I didn’t have to.
We have led the nation for 3 straight years in auto/cyclist fatalities. Great place to get killed so keep your head on a swivel. I ride enclosed paths or indoors only now, Florida is absolutely insane b/c vacationers with their heads in the clouds and the octogenarians with one foot in the grave already. BE CAREFUL!
For swimming you’ve got open water and pool choices in Tally. Check out Maclay State Park’s Lake Hall (watch for gators). The park’s a solid place to run too. The surrounding area actually has hills (shocking for FLA). Trousdell pool has a long course set up. Check out the FSU Triathletes site. They can offer insight too. The St. Mark’s trail is flat & you can turn off for some nice rides (go to the lighthouse).
If you come to the Jax area, we have a bunch of group rides, take a look at www.velobrew.com for a decent list. Tallahassee has some regular rides and good routes, Google Higher Ground (I think that’s the shop name) and the FSU Cycling team for contacts. I know Jack Tomassetti, a local kid who’s president of FSU’s cycling team, is apparently in Tally for the summer.
I live in st. augustine. plenty of good riding here. PM me and I will send you links to rides and group rides. let me know where you are staying and distances you are looking for I will send you all kinds of good stuff