Mountain - Plains - Flatlander Seeks Advice

So I'm from the great midwest, and my brother is asking me about spending a week doing day trips from his place in Keystone. ill I live to talk about it? And how do I train for it? Around here, "hills" are the occasional 30-50' rise.

I've biked through Keystone several times. good MUPs and roads. There were slippery spots on the west side of Vail Pass. Start training hard, anaerobic thresh-hold stuff, time trials, 5 hour centuries. When I was there I was 20-30 years younger, was doing 200+ miles a week and lived at 5,500 feet west of Denver. Stay in Denver for a day the sit in Keystone a day before even trying any hard riding. Adapt to the altitude carefully. Get some gears lower then anything you see where you are now. Pedal up Loveland Pass slowly; no headache? Good to go.

I'm going to disagree w/Ken on the acclimatization strategy. Usually, you are OK the first day, then not so ok for at a few days after that, and then get gradually better over the course of a few weeks. Since you only have a week, forget about acclimatization, you don't have time. Just make sure you drink a lot of water and not very much alcohol, and have fun. Low gears is a good idea. Advil or something like that for the headache. Sunscreen.

The big mountain passes (Loveland, Vail) tend to weigh in at 6-8% grade, with occasional little bits of 10%. Not very steep, but miles and miles of climbing. Can't help you with the hill training where there are no hills.... intervals? thousands of repeats on the freeway overpass? move?

Don't forget your camera. It's beautiful there.

you dont say where you live in midwest
there many places in midwest flat but with 20 mph winds
if you can ride into a 20 mph headwind for miles on end
vail pass from east, keystone to montezuma, dillon to breck ... will be pieces of cake