First, do advanced beginner to intermediate riders ever ride a double crankset in the mountains of CO? I rode a compact double last year in Glacier and had no problems. I worry about the altitude in CO (and some very big climbs!) If recommended, I could rent a bicycle with a triple. I like to climb, I'm just not fast or strong.

Second, the dilemma: I have two bicycles that I could take on my trip

1. Cervelo--Very light, stiff bike with standard double cranks (53/39, 11-26)
2. Cannondale Synapse--Bike that weighs about 3 lbs more than the one previously mentioned, but with compact double (50/34, 11-28)

Thank you for any input and opinions!