RE: Good Mexican Food in Dallas, GA
I don't get to Dallas very often, but east of you are several good or better places. Nuevo Laredo on Chattahoochee Avenue (near I-75 and Howell Mill Road) is very good and always crowded. The taqueria at Supermercado Jalisco in Smyrna has been my favorite - but all tenants of Jonquil Plaza Shopping Center (where I was a tenant for 12 years) are being displaced by a major redevelopment project. Supermercado Jalisco has several locations in metro Atlanta, but Smyrna is the only one I have tried. I am having a senior moment. I can't think of the name of the restaurant at Jonquil and Spring Road (a block east of Atlanta Road), which serves very good Oaxacan cuisine. Try a tlayuda - messy, but good.
Roswell has several very good taquerias - El Azteca Groceria on Alpharetta Hwy just south of Holcomb Bridge Rd/Crossville Rd (GA Hwy 92) is the best in the area IMHO. Across the street is Taco Mas and a block west of GA 400 on Holcomb Bridge Road is Carniceria San Miguel. These three all serve a heavily Mexican customer base and focus on tacos, burritos and tortas.