I have one very friendly dog that loves meeting new dogs and people. He's been with me for over two years now along with two cats that I have had for 3 years. The dog will most likely try to do anything and every thing with your dog if it is an over night stay and the cats will most likely hide in the basement during that time but if not they are well prepared to defend themselves. If your dog is playful with cats they may give your dog a scratch or two but if left alone they will not bother your dog. My dog is very playful with them and after getting used to the dog, the cats will either ignore him until he goes away or smack him but nothing serious in the two years I've had both. I live in a fenced in townhouse within walking distances to parks and have many sidewalks in my neighborhood. If there is an overnight stay, I work ten minutes from my house and can check up on the dogs regularly and have an alarm system that will alert me to any issues such as fires, break ins, etc. so you can have peace of mind while you are away.