if your flight gets in late, 3:30 or so, by the time you collect your bags, get thru customs, rent a car, and get out of the city, it will be 4:30- 5:00. it has been getting dark around 6 or so. the dirt section of the trip is actually pretty good,, right now. but,, it rained last night. if you drive in the dark, you can see all the sites on the way back.
another option is,, fly down and rent a car here when you need it. just for a day or 2 works well and that car is not sitting in the lot while you snorkel or go on another trip.