All the 1940 United Staes Census images are now available and searchable. All 50 states are fully indexed and are free at: https://familysearch.org/1940census/?icid=fsHomeSearch1940Scouts. If you have an Ancestry.com account, they are easier to locate since you can narrow the search parameters.
To date, I have located and downloaded 37 images and the relevant ones are loaded on my website.
If you have not started yet, begin now!