If you want to stop halfway-ish, you’re looking at the upper valley. Besides the Hanover options mentioned by sibling, Three Tomatoes pizza in Lebanon and Tuckerbox (Turkish place) in WRJ are good toddler-friendly places that don’t take you as far off of I-89.

Montpelier has some decent options too, but by the time you’re there you might as well just drive through to Burlington.

Edit: oh, or New Thailand in Leb, just off exit 18. Good food, super convenient from the highway.