Stopping to get fuel, I think is part of traveling......
Which goes to the oft-repeated mantra about rap vs ride. If it's up for debate, or if it's something you have to prove as a defense, you're "more eligible" for arrest and the prosecutor, court and/or jury will figure it out. Of course in lieu of arrest, a report could be forwarded to the prosecutor as well if there are discretionary concerns, but IME that's much more rare than a simple field arrest, initial arraignment and later declined prosecution.
If traveling is construed as an act and if pumping gas, getting a drink and going to the bathroom are in furtherance of traveling as an act, as a juror I'd find you to be traveling.
As TXI notes, case law plays a significant role here since the actual, codified law is still unfortunately vague.
No chance of getting your CHL from Texas or another state?