Mark, since 20 is south of you I'm not sure how you propose to take it to 30, since that means going west at least to Dallas. Unless of course you mean using about 15 miles of eastbound 20 to get you to US 271, which then goes due north to join 30 at Mt. Pleasant. This route is at least an hour faster than going west to get 30.
I hope I didn't insult your intelligence here.