As a long time resident, now retired to near Tyler, TX, I can tell you any of the routes thru Dallas are pretty horrible. Noon time Friday might be the best time, though. It's going to be 1 1/2 hours of white knuckle any way you do it. I would recommend winding down on state highways to Canton, TX, then Kaufman, then Ennis, but that would be about an hour longer and 30 miles further. Good luck.
If I had a gun to my head and had to do it, I'd probably cut off from I75 onto 635 around to I45, then south to Waxahatchie, then over to Ennis.
