Saint Augustine should still have Nights of Lights going. It will be 2+ hrs from the south side of Orlando but we’ll worth it.
Rainbow river is great for canoeing, kayaking, snorkeling, etc. No manatees there (or gators), but it’s a very pretty river and lots of other wildlife. It’s about 1-1/2 NW of Orlando.
Wekiva Springs State Park is much closer and also good for a swim or canoeing. The canoe trip runs through dense growth and offers the opportunity to see alligators, so it can be a lot of fun if you are not from the area. Be aware that the paddle out from the spring is with the current and the paddle back is against current though, so much more difficult.
Crystal River is for swimming with the manatees. This will work best for cooler weather (nights in the 40s or 30s). It’s about 2 hrs west of downtown.
As far as beaches, it depends on what you are looking to do. If you like water activities, the Atlantic is much better than the Gulf. Look further south towards Cocoa, Melbourne this time of year. The water is about 10 degrees warmer than points north of the cape due to currents. If you are traveling with kids a surfing lesson can be quite fun. Just check something like swellinfo.com beforehand for conditions. Offshore winds (winds from the west) and waves in the 1-3 foot range would work well for a lesson.
For a fun (and old) beach town near Orlando, New Smyrna Beach has a lot of options for dining, etc.
On the Gulf side, Caladesi Island State Park (near Clearwater) is worth checking out. Access is by boat only (ferry is included with admission) so it is very laid back and unspoiled.
For spots to check out around the city, Winter park has a good downtown and some nice options for bars and dining. In downtown Orlando the best spots are around Lake Eola and the new performing arts ctr. Sheri’s (sic?) a sushi place and Ceviche (a tapas place) are pretty good from previous experience. Downtown Sanford is an up and coming area (again bars and dining) if you are staying north of downtown.
Hope this helps.
