If I must do "Mexican" fast food then Taco Time would be my general leaning in such matters (never done Taco Del Mar, Taco Cabana once 20+ years ago so eh), though as with others I would rather go to a real restaurant*/decent food truck/make it myself and this means unless it is do or die I will usually starve rather than go for it. Fortunately that has not happened and most people on a road trip know better than to chance such things. They have not joined subway, mcdonalds and burger king in "that is not food, don't eat even if starving" but it is close at times.
*you mean I can have chocolate sauce and it is not a dessert?
Tomatoes and I do not get along whatsoever and guacamole is something I can choke down at best which makes this harder, though far from impossible. I do like refried beans and I do like meat. Soft wraps are my preference in such things too. Whatever comes from that being what I go for.
Also better do a song. Skip to 6 minutes, or don't and watch the whole thing