Well, Foggers,

It's not the best time to visit for festivals in NI. You'll have missed Celtic Fusion in Castlewellan and Fiddlers Green in Rostrevor will just have ended before you arrive. The Ballyshannon Folk Festival, just over the border in Donegal, starts on the 1st August - http://www.ballyshannonfolkfestival.com .

You might also want to have a look at http://www.aoifeonline.com, though its search engine is a bit cranky.

In terms of camping, some of the best sites are in the forest parks - http://www.forestserviceni.gov.uk/index/activities/caravanning-and-camping-in-northern-ireland-forests.htm. There are also some decent municipal sites along the north coast in places like Carnfunnock Country Park and Cushendall, but elsewhere, on the same coast and on the Ards Peninsula, you'll often find yourselves crammed in by caravans.

The best sessions are also around the north coast, particularly in Cushendall and Ballycastle. If you're in Down, there are also good options in Portaferry and Downpatrick. Check http://www.thesession.org for more details.

If you're heading over to Fermanagh, then there's a good campsite at Castle Archdale Country Park and it's not too far from there for sessions in Enniskillen.

Dare I suggest, shamless plug, that you might acquire the new edition of 'The Rough Guide to Ireland' in advance of your trip?