Though Ezra Meeker initially set out to preserve and mark the original Oregon Trail, over time its namesake Memorial Association expanded its scope to include many western trails beyond the Oregon Trail. It enlisted local organizations to help with the effort and to sell/distribute the Association's commemorative half dollar.
One such organization was the Utah Pioneer Trails and Landmarks Association (established September 11, 1930). By December 1930, the Utah Pioneers organization began a partnership with the Oregon Trail Memorial Association ('OTMA") to mark trails and landmarks in Utah. The Utah group believed the national OTMA represented a sound financial partner that could help it achieve its local goals. The OTMA's commemorative half dollar was, of course, a central element of the Utah Pioneers financial plan.
The plan was for the Utah Pioneers to secure half dollars from the OTMA's New York bank and then promote/distribute them locally, with proceeds being paid to the Utah Pioneers. The promotion was to begin in December 1930, and continue indefinitely. The timing of the Utah group's engagement with the coins suggests that it likely initially received 1926-dated coins (Philadelphia strikes and/or San Francisco strikes) considering that it was those coins that the OTMA had in inventory in 1930. (See
1928 Oregon Trail Memorial for more on the topic.)
The coins were to be promoted via newspapers, presentations to clubs and societies, local bank displays, etc. I'm also aware of a special fundraising dinner held in July 1931 that had a ticket price of $1.00 which entitled the bearer to one commemorative half dollar.
The Utah Pioneers eventually erected over 100 historical markers in Utah and other locations throughout the West and Midwest. They were paid for by a combination of membership fees, private donations and coin sales. Today, the markers are maintained by the Sons of Utah Pioneers.
1926 Oregon Trail Memorial Half Dollar

For other of my posts about commemorative coins and medals, including more Oregon Trail half dollar stories, see:
Commems Collection.