Join Date: Dec 2010
Location: northern Deep South
Bikes: Fuji Touring, Novara Randonee
On the bottom, I'd go for medium weight tights, wool socks, and plastic grocery bag halves between socks and shoes. I can usually deal with varying temperatures up top if my legs and feet are OK.
Up top, I'd go with 2-3 thin layers plus the wind (and water) proof top. Over 5-6 hours you can expect some variation in temperature, and you've got to be able to respond promptly so you don't overheat and sweat. Pit zips, play with the zipper, stop and take off a layer (or add one!) if necessary.
If you've got some place to carry them, an extra pair of warm gloves may feel pretty darn good after 3-4 hours.