This is a pretty easy day trip. From 108th to 84th, the water is flat with very little current. The dam is just before 84th St. with the portage on river right. The portage slopes gently down hill but it is a fairly long walk around the right side of the power plant and through the parking lot. The put-in is just upstream of 84th St.
Once you are back in the water, it is a quick paddle to Ruehs park at 68th St. Depending on the water level, you may scrape bottom at several spots.
Take out is river left at the start of the park.
If you get too close to the rapids, just paddle through and use the eddy and you will end up at the end of the park.