Spoke with Marc Cregan, my 300 guy today. He said there is no 'active' 300 group today. He said there used to be a very good Accpac forum but that vanished. Now there is Sage City but that is both partner and customer and he is not comfortable posting certain things there.
I won't give you all the details but there is a TPAC conference every year (3/2015) that we MAY be able to have a printed flyer distributed (haven't confirmed).
Otherwise, I have contacts who are more or less the MAIN go-to people for 300. Sorry, that's all I have for now but I will let you know if I have updates....