After doing some research today — on the Internet, and face-to-face with various other travellers — I've decided that for my time here in Huaraz, I'm going to do the Santa Cruz-Llanganuco hike, and I'm going to do it alone. In order to prepare for this 5-day trek in the Cordillera Blanca (that's the mountain range that it passes through), this afternoon I hired all the gear that I'm going to need, and I bought all the food that I'm going to eat. This being Huaraz — the trekking and mountain-climbing capital of South America — getting all that stuff proved to be no problem at all.
First stop this afternoon was a rental agency, for getting the camping equipment that I'll need. For my equipment, I went to Sechin Tours: they're in the centre of town, and they can give you everything you need. Probably not the cheapest place to rent gear, but I don't think there's a huge difference between the prices of the rental agencies. They also don't really specialise in renting — as with most agencies, they're more into the guided tour scene, and that's what they push to all their customers — but they're competent enough to get the gear out of their shed, and to give it to you.
I got a 5-day rental on a tent, a sleeping mat, a gas cooker, and a pot from these guys; plus I bought two bottles of gas from them. The rest of the stuff that I need, I already have: cutlery, army knife, crockery, backpack, sleeping bag, hiking boots, warm clothes, etc. As for food, I got myself the usual camping supplies: plenty of carbohydrates (rice, pasta, muesli, cracker-bread), plus cans of vegies and tuna, and some canned milk, and plenty of yummies to nibble on. And lots of water, of course. And when you go camping, never forget to bring tea!
Also got myself a map of the Cordillera Blanca, that has my route marked on it. That might come in handy, too. :P
This is going to be the first hike that I do on my trip, without an organised tour company, or a group of companions. I wouldn't do any old hike by myself: but it sounds like Santa Cruz is both the easiest, and the most popular hike in the area; and it's not uncommon for people to do as I'm doing, and to just saunter off and give it a crack by themselves. Everyone says that the route is very well-marked, that the campsites are big and comfortable, and that there are a plethora of other people doing the hike every day, making it virtually impossible to get lost or stranded. So I think that, given my modest but adequate prior experience, I'll be pretty safe and sound heading out into the mountains as a solo adventurer. Should be fun!