Hi,
If you go to the Search button (top right hand corner) and put in Roof of the World May 2017, you will see the review that I did of this fantastic holiday. Due to the fact that most of our group (this was the first tour) got Altitude Sickness, I wrote to JY and they have completely changed the itinerary so that you have time to acclimatize.
I only saw oxygen in one hotel, which by that time, nobody needed it! I would strongly advise seeing your GP about getting a prescription for Diamox, if you can take it. I am also now assured that there is water on the coach at all times.
I hope this helps. Enjoy!
Cheers,
Hils