About the storage rooms, yes, there are some of them in Mount Belnos. I can't remember exactly where it is (as I don't have the book with me), but at least you can find a reference to it in the Adventure Seeds, at the end. A Rhona elder had a vision about it and the PC are "volunteers" to accompagny him. Fresh, well-preserved food for everybody for some months.
Also, about the number of fighters, I suppose that a lot of them are in good physical condition, as they were forced to travel in mountains. So it means a lot of healthy people, not an easy prey. Mentally, that's something else!