I'm looking into renting a moving truck (15ft) and pulling my car across the country from central Virginia to San Fran. I'm wondering what will be the best routes, that is which routes are the straightest and flattest so I don't have to drive too much in mountain/hilly areas?

Also, anybody have experience with the car carrier or tow dolly? I realize with the car carrier the car actually sits on top of the trailer vs. having the front wheels raised as the tow dolly does? However, the car carrier weighs about twice as much. Does this significantly reduce gas mileage? Which is safer to drive with?

Thanks,

Steve