Laurens, If memory serves me correctly, the ride from Miami to Naples is a very desolate road. It cuts through the Everglades and there are not any overnight accomodations. It is over 100 miles from Miami to Naples. Pretty ambitious ride by yourself.
Also, the road is 1 lane going each way unless they have widened it. Not an extremely bike friendly place. Alligators are along the road without any restraints on them. I have even seen gators on the road.