Me and my wife are planning a trip to the states, spring 2011. We want to climb/hike some of the best U.S. peaks in a row: Mount Whitney, Maroon Bells, Mount of the Holy Cross, Grand Teton, Mount Rainier, Mount Shasta and visit Yosemite and Yellowstone in between. We want to go in spring in order to avoid the summer crowds and because we think the spring high up is even more beautiful than the summer.
Do I miss some essentials here?

I'm wondering what the conditions of Rainiers and Mt. Shasta's normal routes are in june (early or late):
How many snow is there left on the mountain?
Are snowshoes necessary?
What about avalanche danger? Snowed-in crevasses?
What about the temperature at night?
Are there some other things we have to bear in mind this time of the year?

Thnx.

Rainier and Shasta are both good mountains to do in June. Ditto to the other remarks. Rainier you HAVE TO ROPE UP due to a large number of crevasses. Go with a guide on Rainier if you don't know how to set up a Z-pulley. Crowds should be low on your concern list when doing these two mountains. Worry about weather, avy danger as well as current conditions. I would Hood in your backup plans!

Also don't worry about the snowshoes. Ice axe, helmet and crampons are required for Shasta and Hood. Rainier requires much, much more.

Your Colorado peaks (Maroon Bells and Holy Cross) may be completely snow covered in early June.

You may need snowshoes for the approach to Holy Cross.

The approach to the Bells may be a long walk over a snow covered road. Beware of the rotten rock on the Bells. You may want a guide.

The Grand Teton will also be covered in snow, but the approach should have a good boot track.

Bring snowshoes for hiking around Yellowstone in case you don't want to post hole in the soft snow in the afternoons.

Rainier may have very heavy snow and avalanche danger until at least the middle of June. In 2008, it had four feet of snow dumped on the Muir Snowfield the second week of June. If climbable, should have a boot track to either the Ingraham Direct or the DC route. Check out some of the blogs.

http://mountrainierclimbing.blogspot.com/

FYI on Holy Cross:

Holy Cross is usually closed until June 20 because of elk calving. Usually it's illegal to climb it in June before that date. Something to be aware of.