I will have about 4-6 days in Belgium (in August) with my father, who is in his 60s. He is not a big city person. We will be coming in from London, and after Belgium we will be staying a day or two in Mannheim.
I feel that Bruges or Ghent or both would be better choices to avoid the "big city" of Brussels. However, I've seen multiple pieces of advice that indicates they are "day-trip" cities. How can I determine which would be the better one for us to stay in?