On Interstate 35 between Dallas and Waco, I hadn't tried any non-chain restaurants beyond the kolache heaven that is the Czech Stop. But the last few drives to Austin put me in a barbecue mood, so I stopped at a couple places you should know about if you find yourself fungry on I-35.
First, there's Michna's BBQ (2803 Franklin Ave., Waco). I found this place courtesy of a review from Full Custom Gospel BBQ's Daniel Vaughn, and all I can say is thank you, Jesus Em-Effing C, for Michna's, Vaughn, the Internets, cow-eating and pig-eating. When you go to Michna's, order yourself 8 million pounds of ribs. They're small but ridiculously meaty, tender and flavor-packed. I also tried the brisket, which had a nice crust but was pretty dry (which the owner apologized for after seeing my plate of brisket leftovers, so I think he might have just had an off day). Compared with the blow-your-face-off-with-taste ribs, the dry brisket was a waste of ribs spots in my stomach. I repeat: Get to Michna's and get the ribs.
Other awesome things about Michna's: The place is filled top to bottom with John Wayne and Clint Eastwood cowboy memorabilia. It's nuts. Your grandpa would shit his Depends in excitement. Also, there's a giant, pistol-shaped smoker that appears to be fully functional. It's a smoker. Shaped like a gun. I think the smoke even comes out the barrel. See it.
On your way back to Dallas, stop at Texas Best Smokehouse (1022 Dale Evans Drive, Italy). The first time I stopped here, a family band was playing live music that made for some seriously Coen Brothers-y background. Texas Best has a nice sausage sandwich, but better is their habanero beef jerky. They sell all kinds of Texas souvenirs, including some sweet-ass personalized pens with names like Ethel and Gladys. I'm going back just to buy an Ethel.
Also of note: The humongo spaceship across the street from Texas Best Smokehouse. It's the Pegasus from Star Trek. It was an arcade, but now it's just got a couple of busted cars out front. It's a film student's wet dream.
Happy travels.