I picked the GCH. There is a chance that you will have cool nights, or even rain. The GCH has a wonderful lounge where you can relax with a big fireplace (also nice to go to in good weather days), and there is an outside fireplace, too. In addition to the big lounge there are some alcoves where you could hang out at outside your room. It is really a lovely hotel.
If your kids would like to sleep in a bunkbed there are some rooms with them. My kids loved sleeping in the bunkbed when they were younger (10, 9).