If you park on the Hydro side, taking the road on the East side of the bridge, you park WAY back and walk to the manned gate where they ask you to hike the rest off road. If you take the road on the West side of the bridge where the gas station is, you follow till its no parking permitted on the road and park road side where its legal and 5min walk to the river entry.
Once they are running, which is now or soon, your odds are as good each side but the Hydro side has a pool you can float roe for ho's if your arms get sore from wrestling Chum all day.