I'm chiming in cause I'm a Texas girl...but I didn't even know where I-10 was to help you out. I about 5.5 hours north of Houston. That's one thing about Texas, you can drive for what feels like forever and never leave the state.
As far as El Paso, I've never been there or anywhere near it at all. However, I've always thought it would be cool to go to the Rio Grande and Big Bend NP. So, if you go, tell me all about it and take lots of pictures. Okay?
We love San Antonio and have vacationed there a lot over the years. We love Sea World and the River Walk. Every time we go to the Alamo, we are surprised at how small it is.
Good luck on your drive and move!!