We're driving MN to CA in a few days and had planned to drive I40 because I am afraid of mountains, and REALLY don't want to do mountains with snow or ice!

However, I'm wondering what the time difference is between taking I70 to Palm Springs rather than I40? According to RandMcNally.com, it's only 1 hour longer to take I40, but it's about 200 miles longer (if I remember right).

Is this accurate? Are there more mountains taking I70, cutting down to Phoenix, and across to Palm Springs?

Our original plan was to take I35 to Amarillo, I40 across to Flagstaff, then down to Phoenix and across I10 to Palm Springs.
Anyone with some advice for someone who is "mountain-phobic"?