I am planning to have a week-long (one-way) road trip from Chicago to San Diego in July or August. Which route I should take-- I-90, I-80, or I-70? I heard a bunch of bad comments about I-70 via Kansas and loads of good things about I-90, but I-90 seems a bit off the direction since I am going south and I would like to get to San Diego within 7 or 8 days. Any suggestions? Any places along the way that are the must's I have to stop? Thanks!