There is good cell phone coverage from Cranbrook all the way to Raduim Hot Springs. In some places it does fade out but not for very long. We make the trip from the Kootenays to Calgary through Fairmount and have always found we had good service.
There is talk about putting cell service through Kootenay Park however haven't been through since mid Feb, so not sure if it has been installed yet. When you pop out at Castle Jct onto Hwy 1 you will pick it up usually pretty quick but weak, and good service by the time you hit the turn off to Sunshine Village
Soup
2018 Northern Lite 8-11 EX Dry Bath
2017 Sierra SLE, 3500 HD / 4x4 / Duramax with a 6 speed Allison Trans
Torklift Super Hitch 20K, 48" Super Truss, front and rear frame mounted tie downs
Fast Gun Long Range SS Turnbuckles, Fast Gun locks