I started by Au just before the Rhein leads into the Bodensee. The streets where mostly flat and there where enough signposts so we progressed well. The Bodensee region is truly a good biking destination. Not only for elderly people and their e-bikes, but also for small children as the bike paths rarely go along roads. Adding to this there are B&Bs and campings in pretty much every village. Towns like Arbon and Steckborn convinced me with beautiful historical archictecture. Last but not least you can jump in the lake whenever you find a spot that suits you.