Pigeon Point Run, Trinity River California

Pigeon Point Run is one of the best Class III year-round stretches of whitewater in California. Although not as popular (or as crowded) as the South Fork of the American River (near Sacramento), the quick shuttle time and beautiful scenery makes the Trinity River my preferred venue for youth group and family rafting trips. In it's 5.5miles there are 5 good class III rapid.
As far as 'backcountry or local secrets' go, if you eddie-out just before Eagle Creek you can hike up a short, steep'ish trail to a neat picnic area nestled in the wooded canyon and overlooks the river.