When I was doing the Western Express in 06, I found that service was available near the interstates such as I-70, but in many places out in the west, I lost service if I was more than 5-10 miles off the main hwy.Are you talking about WiFi or cellular? It sounds like cellular. FWIW, my experience is that for cellular, Verizon is the hands down winner, but there will still probably be days where you (the OP) have no signal.
BTW: Leaving our phones on when the signal was weak or non existent killed the battery fast. It is best to turn them on only when making a call.