There are plenty of Buses and collectivos (shared taxis/minivans) that ply the coastal roads of Peru. The views one gets of the Peruvian desert coast are unreal. They almost remind me of the pictures I have seen of Mars, but its on Earth :). The Peruvian Coast is a vast arid desert and it is the first I have seen of its kind. Sure I've seen other deserts before, but not as arid as the one in Peru. The desert is mostly sandy white with the occasional oasis and town.
In addition, there is a daily bus to Huaras, a town in the Cordillera Blanca (part of the Andes of Peru). The bus takes you from the coast up to the Cordillera Negra. Let me tell you this ride is unforgettable with all the views you get. You start with the coastal desert landscape. Then you go inland following a river and its fertile fields as you go up the Cordlillera Negra. Once you cross the Cordillera Negra, you go downhill towards Huaraz. It is on this last few hours where you get excellent views of the mighty Cordillera Blanca and many of its snowy peaks.
To get to Sechin, the ruins, just take one of the moto-taxis or regular car taxis for a few soles.
Costs are under $1 USD per hour travelled.
Once in Casma, I visited the pre-Inca site of Sechin. The site itself is small enough you can walk around it in a few minutes. It took me longer, cause as luck had it; I spotted the rare desert fox. The site itself is nice. Its walls depict some sort of weird grueling battle in graphic detail. The wall art reminds me of the Flinstone, you know, the one where Fred goes to the social club and wears the funky hats :).
Fondest memory: It took me longer to tour the ruins because as luck had it; I spotted the rare desert fox. It just sat there without moving or nothing. I manage to score a few pictures of it, which I hope, come all right. It is one amazing animal I tell you. It is just Ironic that I liked the desert fox more then the site itself :).