I would take the train into downtown Dallas and stay somewhere within walking distance. What hotel status do you hold, chase, or other?

It is a bit cheesy, but you could always go up Reunion Tower for some views of the area. If you've never been to Dallas, I recommend walking around the Dealey Plaza area. All of the traffic signals and street signs have been preserved from 1963. Even if you are there after hours, it can be a sobering experience to imagine what went on. If you are there when things are open, you can do the Sixth Floor Museum.

For something different to eat, I recommend Chicken Scratch. It would be a very healthy walk from downtown, or a quick Uber.