I trekked Llamac to Cajatambo( a C shaped circuit in Huayhuash) in 7 walking days in '06. Met a friend in country who made the tight times possible. Arrived in Lima at 1am, caught the bus to Huaraz at 8 or so. left the next day in the evening for huayhuash. Including a great one day pissup in Lima 11 days in country, 3 in transit, 7 trekking, 1 drinking. Acclimitization was a bitch (I lived below/at sea level then). Basic spanish was sufficient, in the hills they are functionally illiterate in Spanish and mostly speak Quechua (good luck with that language). food available in country sucked, stove fuel was a pain. The Brad Johnson map was decent, but fell apart.
If you flyfish, bring a rod. Plenty of trout, was able to trade some with the locals instead of the safety fee