How safe is it leaving the camper trailer in national parks/free camp areas when out for the day? We're looking at staying somewhere around 1770/Agnes Waters (Bustard Bay is looking good), but one day we're taking the kids out on the Lady Musgrave Island Cruise, and just want to know how safe it is to leave the camper? Naturally all the valuables will be coming with us in the vehicle, and we'll padlock the doors on the camper and chain the wheels to the draw bar.