I am leaving in about 10 days for the cross country trip from NJ to San Diego.

I am considering the following two routes, but I don't know which one is better.
80, 81, 40, 17, 8
or 80, 81, 40, 30, 20, 10, 8

I will travel with my wife and my dog (30 lbs). We plan to spend 9 days on this trip. I hope we can stop by two places (e.g. just relax in a park and no long driving for 2 days). Any nice place to visit in TN, NM or TX? Please advice.

Thank in advance.