Here are the answers:

A. Atlanta, June (or July) 1984 (see code Atl-16 J)

B. New York, July 3, 1982 (see new photo of Neil & Len from this concert)

C. Philadelphia, February 4, 1984 (code PHL 04 F)

D. Washington, June 25, (what was the year?)

Thanks to Big Rich for figuring out the codes on these passes...