I think he’s thinking of Lockhart Smokehouse in Bishop Arts- that is across 35 and down 30 a bit. If you choose to go over there, I can recommend Eno’s pizza, Boulevardier, Hunky’s burgers, and Veracruz for Mexican (not Tex-mex), as places I’ve been and liked. There are a bunch of others nearby that are also very good from what I hear.
I have heard really, really good stuff about Manhattan Project’s food, and I can vouch that their beer is fantastic. I haven’t made it to their taproom yet- I live in the NE part of town, and work in the south part of downtown a couple days a week.
Rodeo Goat on Market Center between I-35 and Oak Lawn has good solid burgers. And if you’re in the design district, it’s probably walking distance. Meddlesome Moth is good as well- it’s more beer than food, but it still has fantastic food. It’s not far from Rodeo Goat within the design district.
If you’re at the Convention Center for your convention, you’re sort of screwed in terms of what’s nearby- there’s some stuff at the Omni, and a handful of restaurants down Botham Jean Blvd by the police HQ, but not that much, and it’s only sort of within walking distance.
As far as attractions go… I’m kind of at a loss. Dallas is about the least touristy city I think I’ve ever been to/lived in. There’s no big tourist attraction in the area- maybe Dealey Plaza, or Southfork Ranch would hold that title. We do have very good museums - the Perot Museum of Nature and Science is stellar, and so are the art museums - the DMA, the Nasher Sculpture center , and the Crow Collection of Asian Art (behind the Nasher, beside the DMA, by the Trammell Crow center. There’s also the Kimbell Museum in Ft. Worth, which is absolutely a world-class art museum.
If you’re interested in religious art, there’s the Museum of Biblical Art a bit further north along 75/Central. I’ve heard good stuff about it as well.