Hello Jay. I have scouted this section before and don't know how you would run just the rips. The cemetery on the East looks good, but I suspect that would be in poor form. You could put in at the race start and paddle the 2 miles to Dresser. Perhaps stage a bike at the old store on Riverside just North of 95 or portage on Riverside to above the rapid and paddle to your car.
Portaging on the East shore in the woods is no fun at all. Be prepared if you go alone. A swim on Dresser can have you in the water for a good bit. You pretty much need to ride it out until you reach the eddy below.
Thanks Ben! As it turned out I didn't have time to try. I've only done it once in last year's Brew's race, so I was hoping to get more familiar since I live close by. It's interesting to zoom in with Google Earth, shame that there isn't a trail that starts at the LA Water Pollution Control and runs along the river in the woods behind the cemetery.