In reply to Patrick mcbride: think flights are covered now. Good tips on the sports allowance with virgin! And avoid internal changes, can be such a hassle when your bag doesn't turn up :-s
IME Staying out there is cheap if you're staying at camp 4. There is a 14-day per annum camp 4 limit in high season, you should check the National park service website if this applies to you and you wanted to stay longer. There is a kind of black-market for staying longer by a few days if needed.
In april/may this year, loads of lifts to/from san francisco were being advertised so you may not need a hire car. I can't speak for Sept/Oct, but there's always a hook up somewhere!
Food is priceier in the valley compared to outside the valley (stock up enroute!!).
Take very comfy crack climbing shoes. DMM offsets and metolius mastercams fit in almost everything mortals can climb, brass offsets for hard aiders
Savour the moment you first see the captain. It will be with you forever!