Year-Round Off Road Fat Truck Tours. The Fat Truck is an Amphibious-True All-Terrain vehicle, capable of traveling on land, water, snow, mud, or frozen lake and tundra. An eco-friendly tour vehicle with only 2Lbs per square inch ground pressure, this tundra-friendly vehicle may look big, but it travels softly and safely, carrying guests off road to vista views and wildlife viewing along mining/homestead trails, just outside the Denali National Park boundary.