I just ran across this.
I did not really know Chet Ullin but I did talk to him a couple of times.
Ira Spring has a little information about him in his book "An Ice Axe, A Camera and A Jar of Peanut Butter". At one time there was a Boy Scout Camp at Lower Lena Lake called Camp Cleland and Chet was on the staff there when the Spring brothers attended the camp. It is on page 23 and 24 in the book.
Also I have read or heard that Chet had something to do with building the Great Stone Arrow at the saddle above Hagen Lakes on the ridge that runs from Mt. Hopper to Mt. Stone. I thought Ira might talk about it in his book but I cannot find it. Wood might mention it in his trail guide. I will have to check.