I'm involved with a weekly jam night in Knaresborough on a Thursday at the Board Inn on the high street. It is usually pretty much rock based but the last Thursday of the month is now billed as acoustic - which means that they give the drummer the night off although the instruments are still plugged in and we use mics.

I manage to fit my acoustic guitar and mandolin in with whatever is being played on any night and the people are welcoming and will listen to any sort of music even on the rock nights.

Roger

ps

Can vouch for the Traveller's Rest too.