I-55 from Missouri state line north for 25 miles, Verizon coverage is spotty. When I did hunt up around Anna in southern Illinois, I got great coverage from Portageville, Mo all the way to Anna. Can't see that it would change. I-55 Arkansas state line to West Memphis, great coverage with the exception of one place down around Exit 21. I-40 to Little Rock, I get great coverage. Matter of fact, I-40 all the way to Fort Smith is great coverage. Last time I hit I-30 and drove to Texarkana, I had great coverage all the way.

I don't have a clue about TMobile.