Farther south is the rugged coastline around Monte Conero, near Ancona. A well-marked path traverses the headlands here from north to south: starting at the Hotel Internazionale in Portonovo, follow the yellow-red-blue dashes to Badia, then on to Sirolo. This should take you about four hours. The path continues inland for 8 days of hiking.
A totally different environment reigns at Abetone and Monte Cimone, the mountain ridges that mark Romagna's border with Tuscany. Here you can hop onto the Great Appennine Excursion (GEA) inaugurated by Reinhold Messner in 1983. The entire path is 250 miles long, but you can take a lovely four-hour hike starting from Lago Santo, accessible by car. Take trail 5 to the Foce a Giovo, then follow trail 7 to the 6500-foot summit of Monte Bondinaio.
Also along the Tuscan border are the incredibly lush Casentinesi Forests, the most important woodlands in the Appennines. All sorts of hiking possibilities present themselves here, including a two-day stretch of the GEA; you can experience a 5-hour section of it between Camaldoli and Passo della Calla. Or try the 2-hour ascent of Monte Penna from the Camaldoli Hermitage.