I ride Colorado Rockies every Summer, use the Jetting I have right now. Runs great, plenty of air getting to my Vtwin. Been as high as 14,000ft near Ouray & 12,800 ft @ Enginner Pass between Lake City/Silverton,CO. Seen others up there w/No re-jetting & they are running with the air-cleaner lids off to get in more air & sucking in all of that extra dirt thru their filters. Those who do not rejet also have hard starts & down on power & use more Gas. The other Vtwins(Kawies) in our group also rejet(Prairie 650/700's), Cat 650V2's & the Grizz 660 as well, everyone is happy that they did re-jet.
I only went up one step, seems to work perfect. These Keihen carbs/jets really have a wide range in Elevations as I have found the stock jets work fine up to 5,500Ft.
Your location near Chama is so beautiful there, I'm sure you will Never get Bored of the area..

 

You definitely reached some altitudes, especially in the summer when the density altitude had to well exceed 16,000'+. Even with rejetting the carbs, I’m amazed that your ATVs ran at all! I looked at your pictures and you really saw and rode thru some real wilderness areas. How do you guys get your machines to where you go?

After I get comfortable with where the trails go you’ll have to come up and ride some of the pristine trails that just keep going and going. I want to get up to the backside of the Brazos Cliffs one day!

Thanks for the details of what your BF750 can do!
Take care,
Jim