Both the Expedition and Excursion have excellent factory racks so we mount directly to them with either Yakima or Thule crossbars. The 4 door Explorer's factory rack doesn't seem quite as strong and doesn't go far enough forward. We like to use an additional third crossbar with the front bar attached to the doorframes with Yakima's Q-towers or Thule's custom system for Explorer. The back two bars are mounted on the factory rack. Makes a clean strong system for either on or off road travel. We fit Ford Pickups with tents all the time, usually with a ‘lumber rack’ arrangement or a rack attached to the camper shell for carrying the tent - lots of options - ask us. Works great. Broncos, Econoline and Aerostar vans can be fitted with tents also.