Starfish - I do something similar to Pedal Wench every year. I live at about 800 ft. & travel to Frisco & points beyond in the Rockies to ride my bike. Some years are better than others, and this year was a bad one (many reasons not related to riding at altitude). I have found that the secrets to succesful altitude riding are (not necessarily in order):

1. Hydrate!
2. Fuel your body. Try to have something (gel, bar, sportbeans, fruit, peanut butter & jelly bagel, etc.) every 30 minutes or so when you are climbing.
2. Do not expect to be as fast or strong as you are at home - the air is thinner & your muscles are screaming for more oxygen - so take it a bit slower.
3. Keep your heartrate down so you can breathe - switch to lower gears than you think you need.
4. Enjoy the scenery!