Back to start of the thread - Greg - I was there at Cambridge in those days , I met a lovely Canadian girl . You're correct,but,it was a REAL Folk Festival - and not the monstrosity which it has become.
For example if Vin Garbuttand many others of his age group were booked, you'd definitely be in a session in a beer tent with him ,but whilst the present policy of booking mid atlantic "no-ones" persists I'm afraid Cambridge is not what you looking for, so look further afield to a proper Folk Festival a la Whitby , Saltburn and I'm sure Festivals down South to hopefully obtain the sessions and close contact to performers you rightly desire.