Conrad - I wasn't being purposely sniffy or clever-clever - just pointing out that, even in a simple field, people have to have some basic amenities and someone has to organise them in advance. It's just common sense.

The simplest way, it seems to me, to make music in your suggested spirit, is to do what seems much more common in the US than in the UK - to host a house concert. Pressure on the hosts, of course, but most amenities are already in place in a house. US houses, by being larger than ours, on the whole, seem ideal to me for such an event, though you wouldn't a huge number for an audience.