Hi starfish,

All the important suggestions have been made.

And now about the body, the mind and the altitude. People do react differently to altitude. What is fine for one person may not be for another so take this with a grain of salt.

Generally, you will have about 10% less power at the altitude you are talking about, 5,000 ft to about 8,000 feet. Your resting heart rate will also be higher at these elevation. Can't remember the percentage value but i think it was 10-15% range. And below 8,000-10,000 ft, you will only notice small amount of "OMG not enough air! its too thin here" So just go a little slower, drink a lot more water than usual. And as you do the ride, break the ride into smaller chunks in your mind. "I know I can get past that big boulder without getting off the bike" then "I can make it past that tree up ahead..."

WEAR LOTS OF STRONG SUNBLOCK SPF 30 is absolute minimum!! and wear a good pair of UV A/B sunglasses. Even if it is cloudy wear the SUNBLOCK!! UV's do penetrate the clouds and its much much stronger at higher elevation.

And lastly, believe me you will have lots of fun. The route looks really pretty. Hadn't it been for my poor back I wold have done the ride.

ENJOY!!
Smilingcat