This undated booklet mentions that the Inside Passage route through Klamath Falls to San Francisco/Oakland “is expected to be ready for passenger service early in 1933.” So I suspect it is from 1931 or 1932. Passenger service on that route never began, of course, due to the Depression. Except for the front cover, the entire booklet–photos and text–is printed in dark blue.
The Great Northern was still promoting the history of the region: the booklet has photos of the monuments the railway built in 1925 and 1926 and the centerfold map shows the routes of early explorers. Ralph Budd, who led the railway’s historic expeditions, left the Great Northern for the Burlington on January 1, 1932, after which railway marketing of the historical monuments declined somewhat. This makes me lean towards 1931 as the date of this booklet.