I took Afton Lane to get off of Upper Boone's Ferry Road and moving towards the tall trees in the distance where Fanno Creek flowed.
Saturday, April 17, 2021
45.39852222222222, -122.75761388888888
google map 
BOUNDARY 45.3964583, -122.7615738
BOUNDARY 45.4004966, -122.7540481
I took a path between property lines just far enough to see that there might have been a trail before the houses went in. A home owner came out to investigate. He told me I was standing 15 feet about the drain laid for Bridgeport Village shopping center.