Bayard Conservation Area, John P. Hall, Sr. Tract, near Green Cove Springs in North Central Florida is quite an outdoor gem for hiking, mountain biking and horseback riding.
The White Blaze Loop provides most of the opportunity for these activities, with a red trail leading to camping and the river, and a yellow connector trail. The trails seem almost limitless a, weaving through over 10,000 acres and I strongly encourage using the provided maps since, although well-blazed for the most part, there are a couple of markers missing.
The paths are mostly well-cleared so there isn't as much trouble from biting insects as some other trails. The scenery changes dramatically based on elevation and distance from the river, with plenty of opportunities for birding and spotting other wildlife.
I hiked here for several hours following a controlled burn, and the contrast between green and burned brown portions of the area provided some neat contrast for outdoor photos.
The map below shows the full White Blaze Trail Loop at Bayard Conservation Area, requiring about 9 miles of hiking.