I read over Christina's timeline of where they were in the late 1930s and early 1940s and have followed up in each of those places:
I guess you can see why my folks are hard to find. My father was doing a lot of work in the woods during the summers and wintered in Cascade or Emmett with family. They did not really settle down to one place until they moved to Garden Valley in 1950.
Here the family is in the summer of 1937, just the four of them until Cyril was born in 1941 (Mom had lost her first child, a daughter, in June 1934).
With my father's parents in the Cascade census (Thomas and Winnie Logue) was their youngest son, Fred. Below is a picture of him in his uniform as he visited home sometime between 1943-46. His service during the war was at a radar station in Kodiak, Alaska. With him is my father at the left and their father, my grandpa, in the middle. Grandpa passed away in 1954 (as I was beginning my first grade of school).
So, if you are anxious to find your family in the 1940 census, you may have to wait a while longer until the entire thing is indexed, or you can do like I do and spend a few hours a week just pouring over sets of records in areas where you think they may have been in 1940. Whichever, it is fun to look through records that are closer to our day, possibly seeing a celebrity or someone that may still be living.
So have fun looking through 1940. And I will spend every spare minute I have indexing batches of records (right now I am working on Washington state records).