need travel directions

The two most logical routes are; 1/Dallas -Texarkana (Texas) -Memphis -Huntsville. This route passes near Hot Springs, Arkansas which might make a nice stop. Memphis has a lot going on. Compare their famous BBQ with the Texas hill country BBQ you're familiar with.
2/ Dallas -Tyler -Shreveport -Vicksburg -Jackson (Mississippi) -Birmingham (Alabama) -Huntsville. Vicksburg has extensive Civil War historical sites, old south plantations, etc. Great place to stop if you're interested in History. Jackson is nice too. I would take one of these two routes going and the other returning.

I can only really speak to sights to see. From Cedar Park you can either go north to Fort Worth or east to Houston.
I am assuming that you are familiar with Houston but you might go a little farther east to the Beaumont area where there is a town called Kountze. There is a B&B near there but I have not stayed in it.  We did eat at what I think was an interesting place called Mama Jack's. But what I went to Kountze for was the Big Thicket National Preserve which has three different kinds of carnivorous plants.
From there you can venture east to Baton Rouge. You can tour the old capitol, the new capitol (you can go up in the new capitol for free) and go to the LSU Rural Life Museum which has various kinds of houses from pioneer times in Louisiana.
After that go to Birmingham (Alabama). They have a great botanical garden and there's also Sloss Furnaces National Historic Landmark. Also near here is the Talladega Superspeedway and then on to Huntsville.
On the way home go by way of Memphis (lots to see and lots a places to eat), Hot Springs (where you can go the National Park spa for free) and then Fort Worth Stock Yards.