I have done this section.
its relatively easy, with only one climb after you leave cusco (stop at the hot springs the day before)

my blog is crazyguyonabike.com: Author Info: Tori Collins

you can get by without a water filter if you want to carry enough, as everywhere sells bottled stuff
same with food, you will be passing a town every day and should be able to get almuerzos and something to carry. The altitude makes cooking pretty bad really, don't bother with pasta it will be unedible. The bread from the markets travels well.

THe road out of cusco is horrible, it starts out as rough cobble stones (only broken spoke on my whole trip) and narrows until theres barely 2 lanes. THis lasts about 10km then the road widens and improves, and from then on is pretty good.