We are currently in Merida in Mexico and would like to travel to Ambergris Caye. We are traveling on South African and New Zealand passports and are traveling in our USA registered motor vehicle. We have 180 day visas for Mexico and our vehicle has the necessary paperwork. We would like to travel by road from Cancun to San Pedro but cannot see if this is even possible. We would like to spend 3 or 4 days in San Pedro. Is this possible?