to San Diego
the shortest and fastest route is 1300 miles which will take about 19 hours of driving. The halfway point is between El Paso
. If you stop in El Paso the first day will be 8.5 hours and the second day will be 10.5 hours. I would prefer to have a longer first day, but going all the way from Austin to Tucson will be a 12.5 hour first day. The cities between El Paso and Tucson are small and I don't know which hotels in that stretch allow dogs.