Campendium.com lists "Levee Road" on the AZ side as free BLM camping. I have not been there. There are many photos of the area on Campendium's listing for this site.
On the CA side, there are a couple of spots along the river-edge road near the Oxbow BLM camp. Not sure about river access from those.
2006 Tiger CX 4x4, 8.1 L gas V-8, Allison 6-speed