I would not wait for the "Greenlight," from a doctor...
Ask doc how to mitigate around your problems for your hike, then take it with a grain of salt and ask another doc the same for their opinion as well.
And visit the health section of WB.net and others.
Lots of info you need there.
Don't ask if, but how.
Of course there are some problems that may only allow you to do a section at a time.
And if smoking is that hard, vaping has helped many quit smoking and get their breathback, and a majority of the bad they say about vaping just isn't true.
Not a doc. I don't even pretend to be a Dr. on the twebs.