My wife and I are traveling via car from Seattle to Tucson in mid December. We plan on two days of driving time. We have reduced our routes to two choices (potential winter driving conditions) and are seeking advice from people who have experienced this trip via car. Our choices are I-5 south to LA then I-10 to Tucson. Choice two is I-5 south to San Diego then I-8 to Tucson. We have traveled from PHX to Tucson via I-10 many times and were wondering if the San Diego route is slightly more interesting. The posted travel time difference is minimal.