Since you want to stay on I-10 to get to Big Bend, just stay on it. There are loops and by passes around Houston, but if you are not familiar with them, they can be confusing and you can get caught short needing to do a lane change. Even during heavy traffic, you are looking at around 45 minutes to get through Houston and it's certainly not worth drive "hundreds of miles" out of the way to avoid it as a previous poster said. The highway signs are painted on the pavement, all you have to do is follow them. I-10 is for the most part good road and it's not a bad drive. The worst part is the boredom of driving across West Texas. The only tip I have is going across west Texas, stop and top off your fuel when you get a chance. There's no guarantee that the fuel stop you read about in Next Exit is going to be open.