Take exit 1A toward Key Biscayne/Rickenbacker Causeway
Turn left onto SW 26th Rd
Continue onto FL-913 S/Rickenbacker Causeway Toll road (sorry you will have to pay $1.50 toll)
Go straight over the big bridge (enjoy the view) for 2.8 miles and then you will see a lovely sign in the center median that says Central Sewage Treatment
Turn left onto Sewage Plant Rd/Continue onto Arthur Lamb Jr Rd (note- there is a park admission gate there. You will pay $6 per car and $1 for every rider after the first one. (So one driver/rider by himself is $6, one driver plus one other rider is $7)
Go straight and slow all the way to the end…. 1.9 miles