Crossing Texas

There are two roads which basically go from one end of the State to the other - I-10 from East to West (Orange to El Paso) and US 81 from South to North (Brownsville to Perryton.) 

Of course, if you are starting from Dallas, you have to add the mileage from Dallas to the starting point, which can be quite a distance. 

So, for South-North, we would (probably) go Dallas to San Antonio, spend the night, and then on to Brownsville. Spend another night, and then head North. Stops to be determined along US 81 but it's just over 900 miles, so it's probably a two-day drive at least. 

East-West, we would have to get from Dallas to Orange (on the Sabine River, border with Louisiana), spend the night, and then head West. I started doing this plan first, and I think it would be a day's drive to San Antonio, spend the night, another day to Ft Stockton, spend the night and then on to El Paso. Getting back to Dallas, we would probably go to Midland, spend the night and then back to Dallas.