Howdy:
In my earlier life I surveyed the Alaska Highway between Fairbanks and the US/Canada border and from the US/Canada border to Haines Junction for both the military and for the proposed Alaska Natural Gas Transmission Pipeline. Specific to the question regarding Sherman Tanks in Alaska, I have seen no evidence that Sherman Tanks were deployed into the Alaskan Theatre during World War II. There were Sheridan Tanks assigned to Fort Richardson in the 1950's and 1960's.
During the World War II construction period; Whitehorse, Yukon Territory was a mid point construction logistical depot for the ALCAN Highway, the adjoining CANOL Petroleum Pipeline, the adjoining Telegraph/Telephone communication line and the various airfields used to support the Lend/Lease transfer of aircraft to Russia. The WP&Y was heavily used hauling both freight and personnel from the Port of Skagway into the interior at Whitehorse and then north and south along the proposed ALCAN Highway.
The CANOL Pipeline had four legs that centered out of refinery located in Whitehorse; a line that went from Whitehorse to Fairbanks that served Fort Wainwright and the airfields at Eielson, Fort Greely, Tanacross, Northway and the airfields in the YT north of Whitehorse; a line that went from the oil fields in Norman Wells, YT to the refinery in Whitehorse; a line that paralleled the WP&Y ROW from Whitehorse to Skagway and the 4th line that went south to the airfield at Watson Lake. There were pump stations located the CANOL Line to move the various refined products and crude.
The WP&Y was the prime mover of construction material for all of these endeavors but I have seen no evidence that Sherman Tanks were deployed into the Alaska Territory or the Yukon Territory in World War !!.
I hope this answers some of the questions.
Dougwood1954