Why not select one of the countries that David and Katharine are running through for your school term study theme? Or the whole of South America if you prefer?
David and Katharine will start the 5000mileproject in Chile, Cabo Froward (the most southerly point of the contient) cross the Andes into Argentina, run into desert scrub in Bolivia; then to Manaus, Brazil through Amazonian Indian Reserves and over the ancient Guiana Shield into Venezuela, where they will end the expedition in the Caribbean Sea over 5000 miles and 1 year later.