I make the same Mermaid Avenue - Seeger Sessions connection! I can't now remember which one I came across first - a friend introduced me to the Mermaid Avenue album, but I discovered The Seeger Sessions through watching late night television: BBC Four recorded a live performance of the album in a converted church (!) in London, and it's wonderful.
Through good fortune, I've actually seen it twice now: if you ever get the chance, I highly recommend watching it!