The 1st few times I went to NJH I was fine and kept my SATs in mid-90s. After that, I needed to use supplemental O2. At the time, they were able to help me connect with Lincare, who delivered the equipment to my hotel and taught me to use it and picked it up after I left.
I believe NJH evaluates mist patients for supplemental O2 shortly after arrive. If you’re worried, you should ask your lung doc about a HAST—high altitude simulation test to help determine how you will do at altitude.
By the way, most planes are pressurized to 8000 feet, which is higher than Denver.