There’s a section of the Danube in Austria that seduces all comers. Dotted with small winemaker’s taverns, the region, with its curious water-powered ferries and its fruitful orchards whose 100,000 apricot trees blossom every spring, starts at Melk in the west and finishes at Krems in the east. Rent a bicycle from Wachau Explorer’s cycle shop on Krems’ pedestrianised main …