[rockwood84]

a bad radiator cap will let the radiator lose coolant.a bad intake gasket will gradually lose coolant. the cross bar can be moved out of the way to get at the rad cap.you say it overheats while idleing are the fans coming on? the first should kick on a little over 1/2 on the temp gauge if the temp keeps climbing the second fan will kick on at 3/4 or if the a/c is on both fans should kick on. take the cap and get it tested. but if the cap checks good i would think it is gonna be the intake gaskets leaking and i don't think i would use the van for the 1200 mile trip.you would be better off renting a vehicle.the cooling systems on the 3.4 holds air there are two bleeder screws so you can bleed the air.one is on the top of the heater hose right above the water pump. the second one is on top of the thermastat housing. the center turn to the left to bleed until coolant comes out.good luck