The river Lahn in Germany is ideal for recreational canoeing with the family.
There are boat rentals that offer canoes for a day trip. For example in Diez, four kilometers west of Limburg, you can rent a canoe at a reasonable price, put the folding bike inside and go down the river Lahn to Balduinstein. The rental service will pick up the boat there, while the traveler unfolds his Brompton and cycles back to Diez. He will spend the night in one of the country's best Youth Hostels. It is located in the former residence of the counts of Nassau, an impresssive and beautiful castle in the historic city center: Grafenschloss Jugendherberge Diez