I am familiar with the river from Boggans down to the snake. The stretch from Boggans to Shumaker road is similar to what you have done before. Plenty of of drift boats run that stretch and at low flows you may bang a few rocks but no really bad spots. You do not however, want to float the canyon below Shu in a drift boat. The narrows at low water are very challenging and significantly more difficult that Shuwa on the sol duc. We float in pontoons and portage the first drop and then run the rest.