When it comes to kids' spaces, we're all about fun. But with a room that has to function for the kids one week and grown-up guests the next, it's essential for it to be versatile. Sisal, seagrass or other natural fibers are our favorite choices for beach-house rugs and carpets because they hide sand and dirt beautifully. When choosing bed skirts, a darker shade is a great idea because what's near the floor tends to get stained. And it's easy to keep a bright, fun set of pillow shams in the closet and switch them out for younger guests.Finish everything off with an easy-to-wash blanket cover and you've got a versatile room that appeals to all ages, which is especially crucial if you plan to rent. For an extra coastal touch, fill a munitions basket on the wall with wild sea oats.