Take the scenic (and more direct) route:
Hwy 175 out of Dallas to Jacksonville
In Jacksonville, head east on 79 a couple of miles until it hits 204
Take 204 all the way until it turns into 259
Take 259 south into Nacogdoches
see if this works:
really long map url
Went to college at SFA and made this drive every weekend. Hwy 204 is a 2-lane road, but traffic is usually minimal, and I always loved the scenery, especially spring/fall. Even doing it every weekend, I never got tired of that drive. You may even see something to photograph too...lots of small and old towns on that route. It tends to be a little quicker than the I-20/259 route too, since it's almost a direct line.
edit: Took awhile, but finally got the map url right. As an aside, there will be no shortage of Dairy Queens. Also, before you get into Nac, shortly after you pass the 59/259 intersection, there's an old tin building surrounded by weeds next to a body shop on the right. Right outside that old tin building is my old delapidated blue 65 Mustang. It used to be a Mustang grave yard, but all of the other cars are gone now...not sure why mine isn't too. Say hi to her for me.