National buses run along the Panamerican Highway from Lima to Tumbes & some to the frontier with Ecuador. Ormeño  (Lima to Guayaquil daily & Quito weekly), & Transportes Loja (Piura to Loja 3 times daily), have international buses to Ecuador.
If you enjoy beaches, you have to visit Mancora, Colán, Yacila, Punta Sal,Organos and Nunura (for surfers).
Piura, without doubts, is the best place to eat in Perú. Try ceviche, fishes and seafood are always fresh. Another options are leche de tigre (tiger´s milk, obviously is not made of a tiger), seco de chabelo, jalea, etc.
If you want to eat traditional food, you can visit Catacaos city or Sullana city, both have great restaurants. In Piura you can visit El Caracol azul restaurant, La Santitos or Manos Morenas restaurant.
Hostal San Jose (bookable online, around S/25), Hostal America (expensive @ S/55 a night). Both seem acceptable but other than this accommodation is very scarce. (Prices as at June 2007.)
There are frequent combis north to Mancora.