UMBAGOG LAKE, NH Polly Mahoney leads her dogsledding clients, on three teams of Yukon huskies, on a six mile mush around Umbagog Lake to a remote campsite where they will spend the night. Mahoney and her partner Kevin Slater, both Maine Master Guides, operate Mahoosuc Guide Service and lead a variety of dogsledding excursions in Maine, New Hampshire and Canada.