1. You won't "need" a hiking buddy in GSMNP in October. There will be plenty of people along the trail.
2. What is your plan once you get to Davenport Gap and your rental car is in Fontana
{or is this where the "hiking buddy" comes in}.
3. Good news, GSMNP recently updated their website for booking back country campsites/shelters.
They are back to their normal "book upto 30 days before the start of your trip" and campsites/shelters reservations are back to full capacity rather than the half capacity they've been operating.
So you can go ahead and get reservations for your campsites/shelters now for a trip that starts the first of October. Don't wait too long, some dates at some shelters are already near full for some dates in October. You will also have to plan around Cosby Knob shelter currently being closed.
Get your reservations/permit here:
https://smokiespermits.nps.gov/index...PermitTypeID=1