The other guys mentioned that parking is pretty sparse on this river... With the construction going on with the dam (which will go on until 2017). Parking on the east side (Hayward St.) is far more sparse than the west side (287 St, turning into Wilson St) in my experience. On the east side you'd have to walk a bit further to get to where you want to go, but once you get there, you will have more options to choose from. On the West side, just past the trailer park there's parking spots available, just watch the signs as you drive by. It's easy to overlook the trials that go to the river, but it's a fun adventure for you and your dad for sure!
Good luck out there.