Could a young person (is 35 still young?) with strong legs and little money find the same spirit of hospitality that Mr. Leigh Fermor encountered some 76 years ago? At the end of March, I set out to find the answer. With only two weeks free, my plan was to walk from Vienna to Budapest, a 180-mile route that would connect the old poles of the Austro-Hungarian Empire and track Mr. Leigh Fermor’s trail as closely as possible, taking me along the Danube to Bratislava, the Slovakian capital, and across the plains of Slovakia south to Hungary  through three countries whose languages, cultures and histories could not be more different, or more intertwined.

It was tempting, the day I arrived in Vienna, to just walk east from the airport, but I couldn’t completely skip the Austrian capital, where Mr. Leigh Fermor had spent three weeks among the “crooked lanes” and “facades of broken pediment and tiered shutter.” And so I followed his lead, going into the imperial crypt, where the grandest members of the Hapsburg family lay entombed in elaborate sarcophagi, and into the museums, although I shied away from the most famous in favor of oddities like the International Esperanto Museum. And I luxuriated in storied places like Cafe Alt Wien and Cafe Bendl.

But after two nights in Vienna, I was restless. So I crossed the Danube, put on my 45-pound pack and took off down the Donauradweg, a well-kept biking trail that runs from the river’s source to its mouth at the Black Sea. To my right, the Danube, more green than blue, sparkled in the cool sunlight, and I encountered fishermen tending their rods, elderly sunbathers, nordic hikers poling along and cyclists speeding in both directions.

This first day, I figured, I’d take it easy and do only 15 miles. Ideally, I’d need to hit 18 miles a day  about six hours of walking  to reach my goal. It seemed reasonable, especially with the terrain so uniformly flat. The path, sometimes dirt, sometimes paved, would often stretch so far and straight that I couldn’t imagine I’d ever reach the end, and then I’d finally hit a slight turn and face the same thing: an art-school lesson in perspective, complete with the first low foothills of the Carpathians at the vanishing point  and a scampering rabbit to remind me this was no still life.

Even with such straightforward terrain, there were snags. An attempted shortcut through a fuel depot left me with minor scratches and an extra three miles. But such mistakes have a way of turning out for the best. Had I stayed on the trail, I would have never crossed paths, two hours later, at the edge of Donau-Auen National Park, with Jean-Marc and Marie, newlywed French cyclists who stopped to say hello when they saw a lone hiker in the middle of nowhere. They were taking an extended honeymoon: a two-year bicycle journey from their home in Paris  to Japan!