First thing I can think of is wood should not be in contact with soil or concrete. That just makes them wick moisture in and cuts the lifeof the wood in half or more, even pressure treated. If that is not the case and your posts just rot out in 5 years, I think it is time to take the plunge and build it out of man-made products.
Latex Primer: Good for Drywall, that's about it.
Behr Paint: The plastic buckets are good, that's about it.
I think synthetic building materials might be the way to go too. As mentioned, if you use wood posts they need to be pressure or otherwise treated where they come in contact with the soil. 9,000 feet certainly puts you closer to the sun so whatever added UV protection you can get in a stain the better. From what you have said though, it sounds like drying out from the wind is your major issue and I am not sure anything but staining more often is going to help with that if you stick with wood.