you didn't hear it from me, but what if you could walk
A classic problem. I ride to LO from SW a few times a month, and my suggestion is just up Terwilliger to Barbur then then the long easy down grade into town. The top is about at the intersection with Taylors Ferry and the elevation gain makes us wonder if there isn't some other way. Macadam's an SUV bowling alley. .. How about the railroad bridge ? you didn't hear it from me, but what if you could walk your bike over the bridge to Milwaukie and then get to the Springwater Trail? I hope the future trolley extension to LO includes bike path on the right of way.
PS: Use Boones Ferry and Primrose to ease the grade and get out of the traffic on Terwilliger near the top.