We did some exploration in this area earlier this year.  The camp was owned by the Presbyterian church of Portland and it was closed a long time ago.  I'm sure someone else can provide better detail and/or history - I'm not very good at that.

If you go across the south fork where it meets the Clackamas and hike up river along the old pipeline, you will see a trail that takes off uphill near a big downed log.  The trail in that area is rather rough, but you can make it out.  It heads uphill and then there is a faint junction (with an old sign) where the trail takes off south up to near Hillockburn spring.  As best as we could tell, that is where the old camp used to be.  We found the spring, and an old dam, and some old relics (old car springs, etc), but nothing else of much substance.   There are old clearcuts that probably destroyed the trail, and the pieces that were left were rather faint, but we definitely found at least some of it.  Here is a map of when we went from the top end, trying to find more of the trail.