I live near where I-275 & I-75 reconnect, north of Tampa. Here is a suggestion, I have not actually done the entire route by bike, but although busy in spots, it is almost all with a shoulder and might be the shortest distance. I am not sure where you live in Tampa, or if you want to camp or hit motels. Route 301 has motels, camping, restaurants, and grocery stores near it. Starting, say from the State Fairgrounds, take Rt 301 North to Zephyrhills, to Dade City, to Lacooche, onto Bushnell, Coleman, Adamsville, Wildwood, Moorland Park, Dallas, Belview, and into Ocala. Continue north on Route 301 towards Hawthorne. North of Hawthorne you will reach Route 26, turn right east, take it to Route 100, turn right east, towards Palatka. Once you pass the Palatka Airport and cross the water, at East Palatka turn left onto Route 207 north, go through Hastings, Spuds, Armstrong, Elkton, under I-95 into Routes 1 & 5 north which will take you into St. Augustine. If you do 50+ miles a day you should be able to complete it in 4 days.
Trying to pick up the ACO Florida Connector from Tampa, I have not found a route, I felt safe on. Maybe someone, in the forum, could suggest one heading east out of Tampa. I hope this will help you