Hi Jim - we were traveling with a local anthropology professor and he arranged the local guides. There were about 20 in our group ranging in age from 30 to 75. 10 did the longer hikes; about 10 did shorter hikes within the ruins (ie, the walk to the natural bridge was around 45 minutes each way). Both of the longer hikes were guided; the shorter hikes were unguided. It was well, well worth doing but you have to be in reasonable shape to do them successfully.
The walking in the site itself is moderate - some steep areas but well traveled paths. The initial tour was about 3 hours. Lots & lots of steps. If it's rainy or wet, add slippery to the conditions.
There are spots in both of the longer hikes where it is so steep you go down backwards and some areas that required care. The hike up to the sun gate to the waystation is more difficult and was about 7 hours round trip. There's one section where you have to go through a opening over a wooden bridge wasn't long but required a lot of care. The hike up & down the bigger of the two mountains that is within the park (the one that is on the right of all the pictures you see with the ruins in the foreground) was about 2-1/2 hours round trip. Very steep sections, especially if you go all the way to the Temple of the Moon. Getting down is trickier than getting up. It would be easier to do that one unguided as there is a steady stream of hikers as opposed to the one on the waystation.
Miscellaneous other things:
It's possible to get your passport stamped at the main entrance to the ruins. We were glad we took the time to do this.
The prevalence of the alpaca knitted goods: Cuzco has a wide variety of choices. You can get high-end manufactured goods near the Monasterio that are very stylish and pricier. As dd noted, the style show on the Vista Dome home will give you a preview of the higher end alpaca and vicuna products. If you want that sort of thing, you can also pick it up at good prices as the Lima airport.
On the other end, you can also find a cooperative of hand-knitted products in a few of the stores for $35 or so. We were advised to look for baby alpaca rather than alpaca as it is softer. If it's hand=knitted, check it carefully. We found some of them had uneven sleeve length, etc while others were works of art. We were advised you could rely on the labels for accuracy as to baby alpaca vs. alpaca.
Friends of ours found a handmade candle shop with lovely goods in Cuzco. They bought several items and have enjoyed them.
We were offered a 10% discount for paying cash (in soles) vs. using a credit cards. Our ATM cards worked down there with little difficulty in Cuzco & Lima.
Watch your purse, etc. as you would in any large city. We found in most places that if we didn't have exact change, someone from the store would run off to the central "banker" in the market, get change and come back within 5-15 minutes. We were a little surprised the first time this happened but we received our change every time.
Go into the cathedral in Cuzco (it's on the Plaza des Armas). Their depictions of the Last Supper have a distinctly Incan flavor.
Guinea pig is the national delicacy (local language is coy). Not terrible, not wonderful. If you're in the sacred valley, you may see the local people keep pens of guinea pig inside their houses. That's where they raise them.
We loved the Peruvian people we met. They are gracious, cheerful, hardworking and so very proud of their country and heritage. They love to show you their land and are delighted that you're there.
Lima tends to be very hazy - it gets 4 inches of rainfall a year. The clearest times of year are when you'll be visiting. Miraflores and San Isidro are the touristy areas.
There's a great Incan market in Miraflores so you can pick up souvenirs if you so desire.
Enjoy! Anne
