If your travels are taking you inland you can either rent a vehicle, or take a taxi, however, we strongly recommend you rent a 4wd vehicle as we are too far from any tours for you to walk.
Auto Rental Companies - there are several to choose from and they are all located directly across the street from the Belize International Airport. For a list of companies refer to the tab "shopping/rentals" found at Philip Goldson International Airport Belize website.
Taxi - there are typically taxis available as you exit the airport, but you will want to be sure they have 4wd as it will be impossible otherwise for a car to reach Falcon Hill without a 4wd vehicle, so we would Discourage the rental of a taxi.
Because Belize is so easy to get around, we highly recommend the rental of a vehicle (preferably a 4-wheel drive). This will allow you more freedom and provide you an opportunity to explore Belize even more! Falcon Hill is too far for you to walk to any of the tours, so again, we strongly recommend you rent a vehicle.