Lake Constance is the 2nd largest (by volume) freshwater lake in Central and Western Europe, and usually a very crowded and touristy area. So, the best time for a visit is pre-season, and before Easter holidays begin.
We set up "camp" in a modern hotel within walking distance of the old city of Konstanz, which is situated at the lake and its name giver. During our sojourn we spent our time marvelling at the medieval buildings. The tell tale is that city was spared the bombing during WWII because it was feared to hit the adjacent city of Kreuzlingen in Switzerland. Hence, buildings from several eras have survived and were nicely restored and modernised.
Konstanz also has a very nice selection of restaurants, and our choices were Indian and Japanese cuisine.