I was wondering what the best mode of transportation would be for a 5 day vacation in the keys. We are staying at the Banana Bay Resort in Marathon and would like to visit most of the keys(if it's possible). We are not sure if we should rent a car, scooter, boat or just wing it for 5 days via buses etc. Does anyone have any suggestions?

Rent a car - definitely. Scooters on US 1 are dangerous - it's a 2 lane road with huge trucks delivering to all the keys. Also, a boat is too unpredictable(weather) and you'll spend a lot at Marinas. There are no busses from one key to the next so if you want to get around easily rent a car and have fun!

Definately rent a car. There are tons of places to park and most of the keys are so small, you can just walk everywhere.

... scooters? You can't mean scooters! What a novel way to die.

You will need a car. It is not easy to walk and if you rent a scooter you will probably be squashed like a bug.

Travelnut,
I'm curious - how are you getting to Marathon?