Dave, if you haven't settled on doing this trip on your own, I have a suggestion: Tom Lewis and his lovely wife run a small narrowboat tour every year or two that seems to specialize in pubs and festivals. You couldn't ask for better company, and (in case you don't already know Tom enough to be aware of this) I think the two of you would adore each other. Go to this page on Tom's site and cruise down the page for links leading to details on past cruises and an e-mail addy to be on the list for future ones.

Cheers,
Claire