My information on this aspect of the John Wayne Iron Horse Trail is many years old now, coming from a driving tour that the MilWest Railfan group did back in 1999 ??? As part of their convention in Ellensburg, we chartered two 25 passenger busses and drove the R of W from Throp to Easton. On board each bus was a rep from State Parks, who spoke of the difficulties they had in dealing w/ DNR and the Army as well. Recall that at the time, the Army was opposed to allowing the State to use the R of W from Boylston to Beverly as it ran through the Northern edge of the impact area for the Yakima Firing Range. I understand that access is now allowed; however one must first phone the Army Rangemaster and request permission.
I drove the R of W from Boylston down to Beverly in the summer of 1995. At the time the gates were not locked, the signs simply said to close and latch the gate after passing through. I can say that this stretch of the R of W is quite boring, with the view of the Columbia River the only real highlight.