There has never really been a room centered round the "diddly dee" stuff that I know of though I for one enjoy it and I can think of a few "'catters" including cyder drinker and Alison who play it...

I'm UK resident but if I go on PT, tend to be very late. In my experience any room that likes live music will appreciate that sort of music even though some may seem more American/popular/singer/guitar orientated. In fact, one of my favourite experiences was in one of that type - one of the "Live and Unplugged rooms" when somone who goes by thename of "Rowdy Male" recorded my tune (Turkey In The Straw - something I knew he would know) and when his turn came up, he played "me" together with his live chord backing...

I think the bottom line is to be open to trying any live music room (even though some including me at times want just folk) and see how you get on. There is a great community, Mudcatters and non-Mudcatters out there.