Oh my, I love riding along the Clarion... But I'm afraid I've only ever done what you've done (I'm assuming River Rd and Spring Creek Rd are part of your tour?)
Google Maps says the north country trail is ok for bikes, but I don't remember any trails that would have been fun to ride on up there. If you highlight the "bicycle" option in Maps it might give you some ideas, it looks like there's a few trails and paths marked in the area.