There’s a reasonable admission charge, payable in either Peruvian currency or U.S. dollars.
You can make your tour as easy or as strenuous as you care to. Wherever you go, you’ll need to negotiate at least some moderately rough ground, but easy walking trails lead to most significant sites on the lower levels. The going gets rougher and steeper as you progress up the mountainside.
One of my friends --- a VERY serious photographer and hiker --- climbed to the top of the adjoining peak to re-create the famous travel-poster shot.
I passed on that, but here are scenes photographable from some of the easier trails.