Also, on the way to Diamond Peak there is a café right on HWY 28 called the Tunnel Creek Café. Good people run it and they have a very nice menu.
If you drop at one of the back country aid stations you may have to wait up to several hours before transportation back to the start/finish may be available. So, before you make your final decision, find a chair, get some fluids and food into you, and then rest a while to see if you can recover. Many runners in this situation have found this to help them collect themselves and are able to finish. On the other end of the spectrum, if either the aid station Captain or medical staff makes the decision that you are not in condition to continue they have the authority to pull you from the event – Their determination is final.