I live in Naples,Florida and tour all over south/Florida as well as from Naples to Indiana. So here's my two cents:
1. Sarasota to Pine Level campground/Pine Level,Fl. 780 to 70...........40 mi. Camping free
2. Pine Level to Caloosahatchee Regional park/Alva. 70-31-78/River Road..........50mi. Great campground
3. Calooshatchee to Roland Martin Marine/Campground/Clewistion.78-29-78-27-720-27....57mi. Don't take 80...
4. Clewiston to Markam County Park/Weston,Fl. 27-I 75 access road...63mi...

You can take 41 if you don't mine the traffic. You have a decent shoulder/except a short portion of Fort Myers/from Sarasota to 29/Everglade City. You can camp around there and do the rest of 41 Sunday am..