In 1943-1944 10th Mountain Division was training troops at Seneca Rocks in West Virginia in aid climbing, hand signals and use of muffled piton hammers. They likely had first ascents on many of classic climbing routes, although very few were recorded. During their stay the army hammered over 75,000 pitons into cliffs of Seneca Rocks and nearby Champe Rocks and Nelson Rocks, many of them still remaining.

The division trained for one year at the 9,200 foot high Camp Hale. Soldiers trained to fight and survive under the most brutal mountain conditions, fighting with skis and snow shoes and sleeping in the snow without tents. On June 22, 1944, the division was shipped to Camp Swift, Texas to prepare for maneuvers in Louisiana, which were later canceled. A period of acclimation to a low altitude and hot climate was necessary to prepare for this training. On November 6, 1944, the 10th Division was redesignated the 10th Mountain Division. That same month the blue and white "Mountain" tab was authorized for the division's new shoulder sleeve insignia.

Time Frame in Aleutian Islands of Attu and Kiska
June 7, 1942: Japanese forces invade Attu and Kiska, small undefended American islands near the end of the Aleutian archipelago that stretches westward from Alaska. Enemy occupation of American soil makes the residents of Alaska and the Pacific Northwest uneasy. Eventually, the Joint Chiefs of Staff will decide that the 10,000 Japanese troops in the Aleutians will have to be ousted.
November 16, 1942:
The MTC command moves from Camp Carson to Camp Hale. Currently, the Mountain Training Center command contains only one infantry regiment, the 87th. By next July, it will include the 86th Infantry Regiment and two artillery battalions in addition to several specialized units.
June 13, 1943:
The 87th Regiment moves to Fort Ord, CA for amphibious training as part of the 30,000-man Amphibian Training Force 9. Fort Ord is located about five miles north of Monterey, CA. ATF-9’s mission is to recapture the Aleutian island of Kiska, now occupied by Japanese troops (see map below). Supporting the 87th will be two artillery battalions (601st and 602nd FA), the 133rd Signal Company (derived from the 110th Signal Company), and the 229th Engineer Company (derived from the 126th Engineers).
July 29, 1943:
ATF-9, including the 87th Mtn Infantry, embarks from San Francisco and sails for Adak, in the Aleutians, where it will prepare for the invasion of Kiska. The landing at Kiska was on August 15, 1943.

For a complete chronology of the 10th Mountain Infantry Division, 87th Regiment activity in the Aleutians:
http://www.10thmtndivassoc.org/chronology.pdf