I am baking above 5000 ft. What amount of regular flour plus baking soda and salt would be the equal of two cups of self rising flour.

I'm sorry I don't think I have ever worked with self rising flour. I am not sure of the difference between the two.

I live at 5200 feet and do a lot of baking.

For each cup of all purpose flour, add 1 1/2 teaspoons of baking powder and 1/2 teaspoon of salt. Most of my recipes come out better when I add additional flour in this high altitude. For example, when I make cookies I'll add 2-4 tablespoons of flour to the 2 or so cups called for - I also increase the temperature by 15-25 degrees, and cook for a few minutes less. For a cake or brownies, I'll add 1-2 tablespoons of flour.