I don’t know about tacos, but the best fajitas I have ever had were from a cart outside the PX at Ft. Sam Houston. I’ve been looking for that flavor ever since.
In college five or six of us would pull money for gas to drive 60 miles to Nogales, drink the $.25 beers, and eat the $1 Sonoran hotdogs. Imagine a day trip to another country where transportation, dancing, food, and drink totaled less than $8.
https://mobilefoodnews.com/sonoran-dogs-nogales-hot-dogs-food-truck/