The access card names the bank access points and the boat ramps. Treat them as locations, not a statement of permission, and respect any fence, gate or sign you meet on the ground.
As on any bush river, tell someone where you are going and when you expect to be back, carry plenty of water and sun protection, and watch your footing on soft, steep banks. Never wade a muddy river you cannot see the bottom of, and if you are on a boat, wear a lifejacket.