There is free camping available ad hoc on the grassy, large sides of the boat launch parking lot, anywhere you don't see a sign saying "No Camping". Rules are maximum camping 3 days in a 7 day period, no campfires, tents and gas stoves allowed. There is a pit toilet at one end, and a porta-potty at the other. No running water, showers, dump, or utilities of any kind.

It's nothing outstanding, but for free, it was quite solid. It is worth a 10 minute detour from I-5 just to have the sounds of a river rather than traffic all night. There is camp space next to the river on the left as you enter, or plenty of flat, grassy space on the right for your big rig. On a summer Saturday night, there were 6 other campers dispersed around a huge area beside the hatchery.

Closest store was the Shell station when you get off at exit 63. I stopped at Safeway in Kelso exit 39 northbound, or in Centralia exit 82 southbound. AT&T LTE 2 Mbps down/0.2 Mbps up

The river is beautiful... the hatchery looks like a prison, with barbed wire fencing all around. There's some great grassy areas on either side of the boat ramp parking lot, where we saw a tent pitched, but it's just not an area where we'd spend more than a night.

Area was blocked off by gate about a mile before the GPS coordinates with a NO TRESPASSING sign.