Take US1 South into Marathon (about an hour from Homestead and 2 hours from the Miami International Airport).
Once you pass the "Welcome to the City of Marathon" sign you will go through 4 lights.
As you approach the 4th light you should notice an Office Depot in the shopping center on your right, as well as a Walgreens just beyond and to the right of the 4th light.
Immediately after (about one car length), but not at, the 4th light you will see a drive way to the Walgreens.
Make that right and follow it as it curves to the left.
You will then be in the Discount Eco-Divers parking lot, right in front of the building.
Welcome!
Please note picture below of that somewhat "tricky" intersection.