Bus and train network isn't that great in the north. It only takes you to the main towns and you can wait ages for connections. Best thing to do is hire a car, get a sat nav and just drive where you feel like! The Antrim coast up out of Belfast, thru glenarm, ballycastle, portrush, portstewart, limavady then get a 10min crossing from magilligan to redcastle in donegal for a start. There's plenty of b&b and hotels and check in with the tourist board along the way. Anywhere in the north or south is beautiful even in the rain so enjoy!!!!