I came across an interesting master's thesis on the history and archeology of the railroad logging camp at Ladee Flat. Doesn't have much to do with trails, although it includes a couple of GLO maps from 1869 and 1897 which indicate an Indian trail between Warm Springs and Estacada. There is some good historical information, including oral accounts and photos, describing the logging camp and of the advance of railroads and then roads up the Clackamas.
https://ir.library.oregonstate.edu/jspui/handle/1957/5635
The most interesting part for me was Chapter 6: the story of Camp 1. The incline must have been really something to see in operation.
If you've ever been to Ladee Flat, you'll appreciate the author's understatement when she said that "the area attracts people engaged in a wide range of recreational pursuits, some quite incompatible with archeological site protection."