The first place you can not take your dog is the Smokies, so about mile 163 or so to about 78 miles trail north.
I second getting a guide, AWOL's is the current favorite.
Should be ample water, I don't recall having a problem doing that section (14 years ago.) but a guide will show you where in advance!
When you have a backpack on, no matter where you are, you’re home.
PAIN is INEVITABLE. MISERY is OPTIONAL.