In general, the DFW area is not pedestrian-friendly. Sure, there are pockets where walking is possible and even enjoyable—including parts of Downtown Dallas, most of Downtown Fort Worth, quaint main streets of many suburbs, and White Rock Lake. But to get from one of these neighborhoods to another you need wheels. If your sites are spread out, having your own car is the easiest option (as opposed to using a cab or relying on public transportation).
Traffic is reliably awful on most highways and tollways during morning and evening rush hours and sporadically on weekends, depending on construction and event schedules. If you can, avoid driving on highways from 7 am to 9 am and again from 4 pm to 6:30 pm. If you must venture out during those hours, be sure to allow plenty of time to reach your destination—and pack a good attitude.