John Muir Trail

I had an idea last night about hiking the John Muir Trail next year, possibly September 2006. The guidebook says it's 21 days from Yosemite to Whitney Portal, but I'd hope to do it in around 10. There seems to be a problem regarding food, i.e. there is nowhere to buy any. And what you do carry needs to be seriously protected from bears and rodents. Obviously the faster you do the trail, the less food you need to carry. More planning required. Any advice welcome.
Hiking the John Muir Trail

Thousands of tired, nerve-shaken, over-civilized people are beginning to find out that going to the mountain is going home; that wildness is necessity; that mountain parks and reservations are useful not only as fountains of timber and irrigating rivers, but as fountains of life.
John Muir

I've bought this guidebook, which looks pretty good: