Somewhere around 15 years ago an elderly gentleman in our church was telling us about this spot and on one of my trips to Portland I stopped to check it out. At that time the rail was still solid and the stairs intact. The blackberry bushes prevented getting to the bottom, but they have nearly taken over the whole side of the river in the years since.
If you are southbound, you can park just before the fence. If you are northbound, you should probably park at the wide spot before the corner and walk to the cache site. Container is a camo'd peanut butter container with a very bright blue lid, so please rehide it as you found it. I didn't make a huge attempt at covering it up but the bright blue lid doesn't need to be visible.
The starting contents are child friendly, but the location will require you to keep a vigilant watch over your children. Traffic can be surprisingly fast on this stretch, even with a 20 mph corner just up the road.
Left a TB needing to move along.