Roger, as far as taking the bus; I would say "NO".
My wife was teaching a seminar there & her school paid for her trip; I paid a reasonable fee to ride along.
The trip was almost 23 hours & the swaying of the bus, caused many of us to be SICK!
I you want to see the scenery; then a CAR is a good option.
If I had to do again, I would consider Peruvian Air to Cusco & then "maybe" coming back in a car.
Have a safe flight,
PS - for you expats that aren't aware, Roger has been very gracious to offer to bring a few small items with him from OK (US); his extended family was involved in the recent tornados & I am sure we all wish him - THE BEST. Roger has been busy with working to make sure these people are "back to normal" & may not have answered your PM (if it got thru - as mine didn't). THANKS from all of us - expats...