Generally, I prefer not to stay with people when I'm on vacation. I don't like worrying about using all the hot water or accidentally breaking a lamp or putting an unremovable stain on the guest towel or whatever. For the most part, when I've stayed with Sis, it's only been for a day or two, and I can only think of one meal she actually cooked (I was there for Christmas one year...she was already going to cook a meal). We mostly ate out lunch and dinner, and I made a point to bring granola bars for my breakfast (I generally prefer a smaller breakfast and can go without if there's an early lunch).
I'm assuming that like most of her visits up here, Sis (and BIL) will go to a bunch of restaurants, have a lot of leftovers, eat some of the leftovers for another meal and then leave the rest in our fridge <g>.
