Cell service ... along the Alaska Highway expect NO service unless you are IN a community.
Fort St John, Fort Nelson, Watson Lake, Whitehorse, and Dawson City have 4G service now after recent upgrades.
The rest of the communities on the Alaska Highway (Teslin, Haines Junction, Destruction Bay, Beaver Creek) require CDMA compatible cellular phones, which means your iPhone or newer smartphone will not work.
On the Klondike Highway, CDMA compatible phones are required at Braeburn, Carmacks, Pelly Crossing, and Stewart.
On the Cassiar Highway there is NO cellular service. None at all.
Not familiar with "Telco". Could that be "Telus"?