The rental shop is right on the corner by the bridge between the 2nd. and 3rd. hole. Try out my Ultafuge while yer there and buy it. I've never felt unsafe in that area of town except when the cops make me move my camp somewhere else. I wouldn't class the holes as being "extremely challenging" and I'm not a narly boater. I think they are fun. At higher water maybe they get tougher. You can get the flows from the USGS or some of the California sites. Have fun.