There is a great spot, on the left, as you go above the course on Canyon. It's right next to the bike path and there is space for trailers. However, it can get crowded and it's a PIA traffic wise to turn and park there. You can drive a bit farther up the canyon, turn around and come back. There is parking on the right as well, but dragging your raft across the street could be sketchy.
I'm rowing. The 12 footer I've been rowing is just as wide as the 16', and I figure the extra foot on the oars for the Aire won't be that big of a deal. Good test of my skills