Pictures from Steven Schmit
This picture is from late 68 or early 69. The person sitting on the tow bare is Howard Crampton. He was one of the metal smiths on PR-21's crew. PR-26 is in the back round.
This picture is of the PR-21 mech crew. The person on the left is Joseph Nicther, the person in the middle is Aurthur Simmons and the person on the right is Jim Girdner.
This picture is of PR-21 and some of the crew. Unfortunately you cant see their faces.