As a trucker going from NYC area to So Cal and Texas for over 35 years I ran those routes a thousand times and going to ST Louis and down to Ft Worth is the smoothest, flattest, less traffic way to go.Most people just look at the map and go the way they think is shortest when they go RVing once or twice a year. Did it for a living, (over 8,000,000 miles verifiable, accident free miles) put 2 kids through collage driving that way, been there done that. I don't look for the shortest route I look for the safest route with the least traffic and that is the way. I 81 and I 40 need about 2 more lane on both interstates !! Good luck.