Ced,

Thank you for recommending the places in Paris and Lyon for our trip this past June. If you're coming to the U.S., I've only seen some of my own country, but that which I have seen, I'd have to repeat the recommendations for Colorado and California. In Colorado, you can ride something like this (first picture is Colorado National Monument). I recommend going up from the Grand Junction side. But if you have the time, go all the way up and over to the Fruita entrance/exit, and climb back over to the Grand Junction entrance/exit.

Or you can seem something like this in California (second picture is view of Pacific Ocean from Meyers Grade in Northern California). Make sure you take in all of King Ridge and, once on the Pacific Coast, cut back inland over Coleman Valley Road--essentially, do Levi's Gran Fondo. Both of these climbs have 15%+ ramps.