I don't know if you have ever hunted it before, or what your capabilities are, but I highly recommend going with a drop camp. Brian Verrelian (I don't know how to spell his last name) out of Alta Lake (I think the place is called Whistling Pine Resort and his outfitting business is in the Washing Guide directory, I think it's North Cascade Outfitters) is very reputable and affordable.
You can hike in, but the time of the year for this hunt can go from 70 degree to snowing overnight. There are a good number of bears in the area as well, so make sure you take a bear tag. Don't be fooled, this is big and dangerous country. I grew up in Chelan and worked for the initail attack team in 95'.
The deer are still spread out, as you would be hunting the high county mulies, in their summer range. Don't expect to see tons of deer each day, and another hint for ya...use the thermals to your advantage. Get to a good vantage point in a basin before first light, and glass for the first full hour for deer activity...they will bed down, wait for the afternoon thermals (blow uphill/upgulch) and work your way down to them. In the evenning, set up the spotting scope again, and watch the animals. Once you "blow" them out, don't expect any mature buck to come back to the same spot...he will go to his "safety spot" and stay there for several days.
Good luck
