Brian: I think I've ridden some of those roads when visiting my wife's aunt in Beaverton. Do you ride your road bike or track bike? Occasionally you'll see a track bike (with a brake of course!) on the River Ride. It's miles and miles of flat so there's no real disadvantage to a fixed gear as long as you've geared properly. There's a couple of corners where they have to take care, but I've never seen a problem.