Most travelers arrive to Huancayo [1] via bus from Lima [2], a comfortable six-hour journey on 300 kilometers of paved roads. The Lima–Huancayo railroad, billed as the second highest train in the world, is once again running, though its schedule is much reduced and sporadic.
After visiting Huancayo, most travelers return to Lima, but a growing number continue to Ayacucho [3] (8–10 hours), to Andahuaylas [4] (10 hours), and then Abancay [5] and Cusco [6] (10 hours). This is a fascinating bus journey well off the Gringo Trail and on steadily improving roads. If traveled by day, it is completely safe.
The most interesting town in the central highlands—in the whole of Peru’s Andes—is Ayacucho, but for those short on time, it does not make sense to spend 20 hours on a bus to Cusco. Right now the quickest way on is to return to Lima and fly to Cusco, but watch for Ayacucho–Cusco flights in the future.
Plan on spending at least three days in Ayacucho.
Links:
[1] http://www.moon.com/destinations/peru/central-highlands/the-mantaro-valley/huancayo
[2] http://www.moon.com/destinations/peru/lima
[3] http://www.moon.com/destinations/peru/central-highlands/ayacucho
[4] http://www.moon.com/destinations/peru/central-highlands/andahuaylas
[5] http://www.moon.com/destinations/peru/central-highlands/abancay
[6] http://www.moon.com/destinations/peru/cusco