Many grocery stores have healthy prepared foods. My husband is vegan and we have managed to eat well on the road. Even you aren't vegan (I'm not), restaurants with vegan choices also tend to have other healthy options.
We usually take one milk crate full of shelf-stable foods: prepackaged individual milks, peanut butter, crackers, cereal, nuts, Vigo beans and rice (vegan if you leave out the butter), some vegan soups and Nature's Early Choice bean bowls, etc. We make a game out of cruising the health food sections of grocery stores to find new discoveries (we live in a small midwestern town).
(side note: we usually take a crate of Aldi wine to save $ or not have to go to a separate liquor store like some states require-ha!)
Qdoba or Chipotle are 2 restaurants we do not have nearby so they are a treat for us since they have yummy vegan options.
Apps I have found useful:
google maps-search for truck stops, grocery stores or vegan restaurant options
Happy Cow-Vegan, vegetarian or "options" restaurants--user reported restaurants
Truck stop apps--Loves, Pilot, Trucksmart
iExit--this app shows you what is at the upcoming exits on an interstate. For a small fee you can upgrade to pro and see gas prices also. You can also search by topic such as Chipotle , Hotels, Food, Family Friendly Bathrroms---very handy app.