Peru was GREAT!!! when i was there in '73...my wife and i were the only gringos at Machu Picchu when we were there...traveled mostly by 3rd class bus from coastal Colombia to La Paz and back over 4+ months (average daily "cost" was $7 each, including airfare from Miami to Barrranquilla and Medillin to San Salvador, AND all the alpaca woven goods we could carry back) with virtually no trouble...carried backpacks and sleeping bags, but had few opporutinies to "camp"...used the sleeping bags in hotels in the Andes (no heat in rooms/thin blankets)...
but that was before Sendero Luminoso/the Shining Path "revolution" was causing so much trouble for Peru...with Guzman (the leader of the pack) in prison, the war has declined in severity, but hasn't gone away completely...
depending upon where you are in Peru (high Andes vs Amazonas jungle vs Pacific desert), it's very different...
my work (past 20+ years) at the Texas Dept of Health has been health consultation for international travlers...there are several immunizations/antimalaria drugs that are routinely recommended for travelers to Peru, but vaccines take about 2 weeks post-receipt to become effective, and some (typhoid/cholera) aren't all that effective...do you have experience in other places where there is no safe water??? ...Peru is where cholera was re-introduced into the Western Hemisphere in 1991 (more than a million cases/ 10,000 deaths in Peru alone since then...primariily water-borne), but the previously available cholera vaccine was so ineffective CDC did not recommend its use by travelers... malaria and yellow fever (3 unimmunized US travelers to the Amazonas have died of yellow fever since 1996, including a Texan in 2002...see MMWR, Vol 51 No 15, April 19, 2002) "happen" in Peru, but neither are a risk in the high Andes/coastal desert/urban areas...
bottom line...be VERY CAREFUL about what you eat/drink, get as few bug bites as possible (CDC recommends repellents that contain DEET), NO dog bites (risk of rabies), and WATCH OUT!!! for the bus (accidents and injuries are at least as great a threat as are exotic diseases, and you don't want to need health care in Peru)...if you're there for more than a very short time, expect diarrhea...Cuzco is about 11,000' elevation, MP is about 9,000', Lake Titicaca is about 12,000', Lima is on the coast...it took about 4 hours to fly from Lima to Cuzco and a couple of days to get comfortable breathing-wise, and this was after having already transversed some of the Andes in Colombia/Ecuador (Quito is about 9,000')...
que le vaya bien...