Tender Hosting looks after eight homes on the East Coast and the Gulf. On Plum Island, three units sit on the dunes with decks facing the Atlantic. In Cape Elizabeth, a century-old pine cottage looks over Hannaford Cove toward the lighthouse. In Palm Beach Gardens and North Palm Beach there are single-story pool houses with fenced yards that welcome dogs, and near Siesta Key a two-bedroom condo sits up in the trees, a walk from the sand.