Nothing bad can be said about Lizard Head Pass or Wolf Creek Pass(10,850), I just think the Million Dollar Highway
http://en.wikipedia.org/wiki/U.S._Route_550 edges them out. All three are quite nice. I agree that May is a bit early, but I think it will be doable, and we are talking about a U.S. Marine.
Here are some records for the state of Colorado:
Highest Average Annual Precipitation 45.35 Wolf Creek Pass 1 E
Record Maximum Winter Snowfall 807.0 1978-79 Wolf Creek Pass 1 E
Highest Average Annual Snowfall 434.8 Wolf Creek Pass 1 E
Good call on cedar breaks valygrl, almost 10,600. A deviation from the Western Express may be required, the road may not be open.
http://www.nps.gov/cebr/planyourvisit/roadclosures.htmAlso note that Red Mountain Pass is not 8,970 as I stated before and the CO bicycling map erroneously shows, it is 11,018.
Tim you can see photos of all three of these variations here:
http://tsteven4.qwestoffice.net/gallery/index.html?albumid=5361805162126665921&si=1