Advice on Chris Coole's cover of "Six Days on the Road"

Hello all,

Looking for some advice on playing Chris Coole's version of "Six Days on the Road" by Dave Duddley.

Link: youtube.com/watch?v=cHxzO2WMVFg

I think the gourd banjo tuned way down and fretless is making it hard for me to figure out the tuning or a general starting place.

Any advice you have as far as tuning or any kind of tab for the intro would be greatly appreciated.

Thank you,

Hugh