For families who want a full-service hotel and non-partiers who can afford it, the Four Seasons Hotel is, at 424 rooms, one of the few moderately-sized (by Las Vegas standards) upscale accommodations on the Las Vegas Strip. Without a casino and situated at the extreme southern end of the Strip, putting it out of earshot of much of the frenzy, nothing about the hotel connotes “Vegas.” It could be a Four Seasons just about anywhere: the same serene ambience, the same classically stylish rooms, the same attentive staff, and the same bending-over-backwards for children. One of the secrets of the hotel’s success, however, is that the Four Seasons is actually a five-floor hotel-within-a-hotel, with a private passageway connecting it to the casino of the giant Mandalay Bay Resort. The pairing works because Four Seasons guests have their own private driveway, entrance, check-in, and concierge service. And if the quiet pool at the Four Seasons should prove too tame for a kid with his heart set on tubing down a lazy river, the Mandalay Bay attractions are all available to him, too.