Your route should take you through Columbus and New Braunfels, Texas. I’d recommend Schobel’s Restaurant in Columbus (the original location) or the new one in New Braunfels (which I’ve not tried, but I’m sure it’s a good place with a picturesque setting on the river). Good food and kids’ menus as well.
Okay…I can’t post the link to their website, but if you google “Schobel’s Restaurant” you’ll find links.
I heard one remark that the New Braunfels location was closed, but their web page gives no indication of that. If you plan on eating at that location I’d suggest you call “just in case” the rumor is fact.