I've done most of this but not all of it:

First leg. Easy pavement to Huarcapay. No worries (except for road traffic)

Second leg. Gravel when I did it but easy pedaling. You are following the Urubamba river into Pisac.

Third leg. Easy cranking on pavement, still following the river on the valley floor.

Fouth leg. Asphalt switchbacks and a long uphill.

Fifth leg. I've only been about halfway to Pachar when I was piddling around exploring so I never did the loop to Rapchi and back to Cuzco. If I'm reading these images correctly, you have misidentified the salt pans. Look directly above your thumb tack. See that white skinny oval nearer the top of the image? It's just under the green line which is the Urubamba river-that's the salt pans. They are located in a narrow slot canyon on the descent back down into the Sacred Valley and you come out near Urubamba. So to see them as a side trip on this route, you will lose some altitude and it's downhill getting to them and then an uphill as you double back to return to the road to Pachar. I like this route b/c your first day will be easy cranking and will give you a chance to adjust to the altitude. Never play chicken with car or truck drivers in SA. You have no right-of-way as a cyclist so ride very defensively. If you are interested in Inca ruins, the only upgrade to this route would be to go on to Ollanta and check out the ruins before doubling back to the bridge across the Urubamba that will take you to Maras.