Here's all you need to know:
It's on the low side right now.
From the putin, you can walk down the bike path a short distance to see entrance exam (the first real rapid).
For slaughterhouse falls, there is a big slate cliff on the left and a large sandbar on the right just above the falls. Scout right. Google "Slaughterhouse Falls" and you'll see some pictures. It's quite recongizable and easy to eddy out and scout at low water. I think the "easy line" is about a paddle length off the left bank, but that may be for medium flows. I've heard of some bad shit in the center/center left of the falls from locals (caves, etc.) Not sure about the truth on that.
Below slaughterhouse there is one more larger rapid (name escapes me). There is a large eddy above and an obvious horizon line, so you'll find it. At low water, I recall that rapid being more pinney than anything.
Otherwise, everything is slow and manageable at low water.