While, like Roger, I'm dubious of a new series, I thought I throw another name into the ring for Uncle Jesse's part. That man is the musician Seasick Steve. Ok, he's more of a bluesman than country, but here's some of the reasons I think he might work: 1) He already has the white beard and wears plaid shirts, bib and braces and John Deere caps. 2) Although he's originally from California, he spent some time living around the Mississippi and Tennessee area. 3) Success came to him late in life, and one of things he bought was a tractor - he says he's not into farming, but enjoys plowing. 4) He's a really down-to-earth guy, and I can't find a bad word written about him. I think most of his success has been in Europe, and I'm not sure how well known he is in the US, so here's a couple of interviews with him. Both feature different custom-made guitars he uses that were created from very unusual objects: Seasick Steve on Top Gear
Finally, the man can play. Here's the performance that got him noticed. The song was also the title of his first successful album - "I started out with nothin', and I still got most of it left":