Second part… it would be about accommodations and security. Here in Lima, there are a lot of backpacking hostels near Miraflores, here you will find EVERYTHING you need from food, clothes, to handcrafts and equipment for travel. Moreover, it's a safe place to stay and walk anytime, day or night. Downtown is not far from Miraflores, but is better to go in the morning or not to late in the afternoon. You will find several museums (larco, gold, inquisition), archeological inca sites (pachacamac, and a lot of "huacas" around lima), and many spanish term buildings and churches (historic center -downtown) If you like this kind of buildings, you can take an afternoon to visit them, insides are really amazing specially the cathedral. Always be aware of your camera or wallet even in you are in a restaurant, not because the city is VERY dangerous, but because is better to prevent just in case.
Tips for security all over Peru: (in my opinion) - took only necessary stuff for the day. left the rest at the hotel, of they have security boxes or something like that. - avoid showing your full wallet at street. (credit cards, for instance, but if you go to a restaurant is ok) - ask: in every place or city you will be, hostel or hotel will give useful information about where to be and don't. Also, ask in commerce or restaurants, or at street of the person looks really confiable. Even though I've been in Cusco 5 times, last time I appear in market and I didn't notice!!! because I was walking around without a map....
About accommodations.... In other cities, you should reserve in advance, most of them have little web sites or email. You should arrive and look for one if you want except (again in my experience): when you arrive late at night or, there is a special date in the city. Last time I went to Huancayo every hotel room was full because there were two special dates and Caminos del Inca rally, so I looked it in advance. Also you can call, calling to other city is not expensive less than 1 sol (1 sol right now is 3 soles = 1 dollar, 4 soles = 1 euro) Circuits: I think that there are 4 Basic zones to visit in Peru.
Zone 1 - To the north, beautiful beaches, and preincas cultures. Most important Cities: Piura, Chiclayo, Trujillo, Cajamarca (You can do the trip in one way)
Piura is near the border to Ecuador, best thing to do there, visit their beaches, in Piura and Tumbes (to the north). Mancora is the best for rest and visit, but you can visit more such as Colan (less commercial, almost private). Catacaos is a nice place to buy handcrafts. This zone is very hot all the year, there is a large desert (Sechura) and a natural reserve in Tumbes (Manglares). Chiclayo is famous because of Sipan Museum, near the city. Around Chiclayo, in Lambayeque, and Ferreñafe, there are several site museums, with native pre incas cultures, note that this cultures, are full of gold, that the incas inherit then. explanations about culture, exceptionally realistic handcraft, gold, and buildings are amazing. Food in this zone (Piura and Chiclayo) is abundant in mixes, with sea dishes and other different kind of animals (cabrito, duck) and native vegetables. Sometimes it would be spicy, you should ask. People in the north is gregarious, happy and easy going.
Trujillo has a beautiful group of colonial buildings, and Chan Chan city, which is made of adobe and Huanchaco beach. At this point all the cities are in the level of the sea. Cajamarca is about 2500 meters over the level of the sea. And culture is quite different from the coast. This is the agriculture and farm paradise. You should ask for a lot of products derived from milk. Exceptional landscapes in many places. It is famous mostly because here Incas and Spanish define the begin of the conquer by spanish to the incas.
Zone 2 (I think i'm taking to long!!! but hoping that if is useful for you) - Center: Huaraz: adventure here if you want to climb the andes some adventure sports and/or visit preincas site of Chavin. Also, you should visit strange places formed by 1970 earthquake (Yungay). Huancayo: Valle del Mantaro's capital. You should reach by train, the trip has beatiful landscapes for photos and pass through the tallest railroad of the world at Ticlio almost 4800 meters (amazing landscape at this tall...) Chanchamayo: (on the route to Huancayo, you should take a detour). This is a zone famous for the delicious coffee. Important Cities here. San Ramon, La Merced, Oxapampa, Pozuzo, Satipo, Villa Rica. They are full of waterfalls and rivers, full of river fish delicious. Every city you visit, you are more inside the jungle, but not the big jungle, a moderated one. Also is curious to mention that, when you arrive to Pozuzo, you should be like in Austria's Alpes. There are European colonies and they look like inmigrants but with weird accent!!!
Zone 3 - South of Lima: Better to say that, this was the zone of 2007's earthquake, and you should'n visit for instance downtown pisco, (or only if you want to do some social volunteering) but Pisco/Wine producers more to the south and Paracas Natural Reserve and Nazca lines are ok to visit. In fact, they are promoting tourism in order to have resource to reconstruct the affected buildings.
Zone 4: - Andes, high altitude places, mountains, Incas Empire. People here are more laconic, but always nice. As I wrote before Lima-Ayacucho-Andahuaylas-Abancay-Cusco-Puno route I did this June, was amazing!!! Ayacucho is a place full of churches, is not a big city but has 33 beautiful colonial churches.... Andahuaylas is a very commercial, not big city but its attractive landscape is importante to consider, for instance, Pacucha lake. Abancay is one of my favorites, only 10 km far from the center of the city there is the Ampay Natural Sanctuarium, if you walk the whole day you can reach a couple of lakes and drink natural water from the mountains!!! Cusco, I think it would be one of the highlights of your trip. Important note!!! If you want to do Inka Trail, reserve in advance, since now if possible. You could manage any other attractions there, but also reserve Macchu Picchu train tickets in advance if possible, only to be ok. I will not describe in detail because it will take to long, but city is full of mixed colonial/inca buildings, people from all over the world, nice places to eat,drink and dance. Beautiful museums. Puno, finally... is very high!!! is not to cold by day but it is by night. Be sure to find a place with adequate resources for cold. Lake Titicaca is... simple amazing.
Zone 4a: Arequipa
Arequipa is the second largest city in Peru. It is not very high, but enough for being aware of it. It has all the things you should find in other colonial cities, plus, a huge sleepy volcano, and exceptional architecture. Also near the city is Colca Valley, its Canyon one of the deepest and with sights as beautiful as others. Also you can see natural Condor habitat and eat several river and sea dishes. Other Special Places: - RainForest: Iquitos.... amazing city, there are also lodge really INSIDE the jungle. - Chachapoyas: between Cajamarca and Iquitos, most known because of Kuelap fortress pre inca buildings. - Huanuco and Tingo Maria National park.
I'd visited all the places i've listes except Chavin, (it is not very close to Huaraz), Kuelap, Manu and Colca Valley.... and many more!!! it is a neverending list!!!! Well hoping information would be helpful.... Keep my notes, and when you have time you should ask me more or maybe when you arrive, have some coffee or drink and explain you more about some places. Take note of the places you should reserve in advance, so you won't miss anything. Well let's keep in contact and good luck...