Several good parks opperated by the US Army Corps of Engineers along the Snake River, including: Hood Park, Charbonneau Park (above Ice Harbor dam), Fishhook Park (good dock system for overnight moorage, remote, popular in summer, nice place), Lyons Ferry Park (near Palouse Falls). 25-Mile Creek State Park on Lake Chelan (short run up lake to Steheken). Along the Columbia River, there's Crow Butte and Mary Hill State Park, but the water is usually rough. Been to all these parks with my boat. They're kid/group friendly. Heard that Steamboat Rock State Park on Banks Lake (near Grand Coulee Dam) is really good for camping, boating, quads, etc.