I'm 99% sure the US Army Hospital scenes were filmed in Yosemite
The big white building looks suspiciously like the historic Wawona Hotel in Yosemite National Park, California.
I found lots of pics of it at www.virtualtourist.com/hotels/North_America/United_States_of_America/California/Yosemite_National_Park-756823/Hotels_and_Accommodations-Yosemite_National_Park-Wawona_Hotel-BR-1.html
or
www.historichotels.org/hotels/Wawona_Hotel.htm