Most of the early activities in the early Pacific from Mexico to Alaska were interconnected in some way or another. So most archives and university archives along the West Coast will have information you are looking for.

You can check the British Columbia Provincial Archives in Victoria, the Hudson's Bay Company Archives in Winnipeg and the archives of the University of British Columbia to start with. There is a museum and fur trading archive in Oregon in Oregon City containing information about Dr John McLaughlin that might be able to help you as well.

H. H. Bancroft hired many assistants to perform research for him. He hired a widow from Oregon who wrote many stories about Oregon and the Pacific Coast, but made her turn over all her research to him as a condition of her employment. He claimed her research as his own and gave her no credit for her work. When she quit working for him she continued writing and publishing history books under her own name. I am unable to recall her name at present. Her last name was a hyphenated combination of her first and second husbands and she wrote fiction before she became interested in the native history of the Pacific. I do recall reading that she gave all of her research to the Oregon State Archives though. If you can find her name and who has her research you should find the maps you're looking for. I hope it can help you.

Francis Fuller-Victor is the lady I was talking about. She wrote The History of California, The History of Oregon and The History of the Pacific States of North America plus many other books while under contract to H. H. Bancroft.

Her research was given to the museum made out of Dr John McLaughlin's home.