Dennis- I have some Prosser's in my family tree that moved to Coeur D'Alene ID... not sure if they will be of relation, but its worth a try.
Burt (Bert) and Martha(Lester) Prosser lived in CD'A in 1930 and they had moved there from Jacobs, WI. Burt's brother Earl LeRoy Prosser had moved that direction as well and eventually ended up in Superior, Montana. Their sister Martha (married a Vincent O'Connell) was in Walla Walla, Washington at that same time. Most of this family were loggers or in that trade in some way shape or form.
They descend from John Albert Prosser (dob @1867) and Annie (George) Prosser (dob @ 1870) and these two had an overabundance of kids in the Jacobs, WI area.These kids were as follows: John Jr. dob @1890- Bertdob @ 1892 Earl LeRoy dob @1894- Moved to ID about 1919 Martha dob @1896 Allan dob @ 1898 (my great grandfather) George dob @ 1899 Walter dob @ 1902 May (Charlotte) dob @1904 Mila dob @1906 Theodore dob @ 1908
Im not sure if this helps any, but it is what I have to date... any other questions, just let me know and I can try to give you more, if needed...