I will be driving from LA to NH in mid-August. Our car has NO AIR-CONDITIONING- and I am also a scaredy cat about mountains. So I-70 is out... there's always Route 66 (sort of) but the no AC... the other option I can see is driving back up the coast (we'll have come from seattle to LA already) and taking I-90. How bad are the mountain passes in Montana andWashington on the I-90? Does anyone have any other ideas???