Unlock Vehicles:
Dodge T-Rex: Finish in first place in season four of career mode in the power division
Humvee: Finish in first place in all of the first 3 seasons of career mode in all divisions
Monster Truck: Complete all 36 tracks in single race mode
Rod Hall Hummer: Finish in first place in all divisions in career mode
Shelby Dodge Durango: Finish in first place in season 4 of career mode in speed division
Pro-Class Trucks: Complete the first 9 tracks in single race mode
Unlimited Class Trucks: Complete the first 27 tracks in single race mode
Moon Buggy and Moon Level: Run over all 9 of the Blue Moon Cafe signs. There are 3 in Moab, 3 in Hawaii, and 3 in Yosemite and you can do this in Free Roam or Career Mode.