My brother used to work there so I know it pretty well but the last time I was there was a couple of years ago.
If we get all the rain that is forecast I would not count on the Castlerock section even being open. Not much snow making or grooming going on in that part of the mountain. Its sort of like a MRG section of the Bush. The must do terrian will be the groomers and where they are blowing based on the likely snow conditions.
Allyn's lodge used to be just a warming hut but now on their web site it says they serve food there. The lower level of the Glen House on Mt Ellen is more of a warming hut type place where you might be able to BYOB. My recollection is that they may not be all that cool with BYOB so better keep it low key.
"Life is like a snowball, the important thing is finding wet snow and a really long hill" Warren Buffet