A "bummel" is a journey without end. Whether we want to or not, most of us have to settle with a return to our regular exertions.
So do these heroes of THREE MEN IN A BOAT, only on this occasion, a cycling trip through the Black Forest, it seems they may cycle on forever, such are their problems. Whether it's George attempting to buy a cushion for his aunt or Harris's harrowing experience with a road-waterer, not to mention the routine problems with language and directions, things get very confused indeed!
"A delightful excursion in a world which, alas, exists no longer--and indeed may only have been found in the author's lively imagination." (B-O-T Editorial Review Board)