I just thought I'd give you all an update. We got our portable oxygen (provided by the VA, but only because a non-VA doctor ordered it) and my husband used it while driving into the higher altitudes and nearly all day, and every night. However, we found out the altitude is not the only concern when traveling above 7000 ft. It was so dry that we had to run the humidifier, which affected the way the O2 machine worked (especially at night). It'd get stuffy, so we would want to run he ceiling fan, which affected the way the O2 machine worked (especially at night). It was actually quite a NIGHMARE! To literally have his life be dependent on a portable machine that didn't operate all that great (humidifier, air flow, needing to depend on an extension cord), his O2 levels went extremely low and we packed up and left after a few days. Breathing was a constant worry for him and his well being was a constant worry for me. Which means, no activities, no sleep. I had every reason to worry, as his O2 levels went dangerously low at times. It was a horrible decision to go and we will NEVER go to such a high altitude again.