Is there a place I can find information on early rangers for Crater Lake National Park?

If he was employed by the National Park Service, the National Archives at St. Louis may have a civilian Official Personnel Folder for him. See https://www.archives.gov/st-louis/archival-programs/civilian-personnel-archival/index.html .

The National Park Service often keeps park records at each park rather than having the National Archives accession them, so you may have more luck finding documents and images you're interested in by using the Crater Lake National Park archives.  Their website is here: Collections - Crater Lake National Park (U.S. National Park Service)