The confluence is easy, especially at this level. The only thing you have to look out for in there is wood, an thats where a squared back end of a row boat can really get you in trouble. My Dad floated us down the Sky from Ben Howard to the Douglas Bar on the Snohomish in a 12' Sears Gamefisher a hundred times when we were little kids. Usually in the spring during catch and release for steelhead. We never had any issues, just paid attention. I've done it numerous times in the last few years myself duck hunting in there, same deal, just pay attention. A driftboat is definitely safer though, and a much better fishing platform, so if that's an option, I'd do that.