I really liked using the Hiker Hostel as a package deal to get from the Atlanta Airport to Springer (or Amicalola) with fuel provided and a stay in their hostel and breakfast ..., I think their $70 "thru-hiker special" is a great deal.

If you start in reasonable shape and your gear weight isn't too bad, then 10 days to Franklin seems reasonable to me --- I started from Amicalola falls on Feb 25th and got into Franklin on the morning of March 6th this year, i.e., 10 days, and that included a Nero in Hiawassee along the way. But what seems reasonable to one person might seem pretty slow or pretty fast to others, "YMMV" ... !

For just 10 days I personally wouldn't worry about avoiding particular foods; Mac n' Cheese etc are pretty lightweight options (are you seriously bringing canned food?!?).
I also don't see the point of mailing food to Mountain Crossings when they sell food there, but each to their own on that sort of thing.