Any good non-campground places near Grand Coulee?

We're thinking about a trip out that way this weekend to escape Seattle rain and hike Steamboat rock, but not at all familiar with the area. We prefer to find a FS or fire road and setup camp away from the crowds. Any good suggestions?

 

I've stayed at Spring Canyon Campground in late September. It was nice and pretty empty, but I suspect that it might be packed with boaters this time of year. There's an Indian reservation to the north and farmland to the south, so I don't think there is much dispersed camping to be found. That's about all the information I can offer. Hopefully someone has something more.

 

Little late to the party but Spring Canyon is nice, last time I was there (8-9 years ago) there was also camping at the base of Steamboat. There was also camping at the West end of Banks Lake at Coulee City. Gotta be careful camping in that area, especially off the beaten path as there are rattlesnakes all over the place.