I guess I must be fitter than I thought
I'm blessed with a mostly smooth rail trail near my house and when it's quiet there, I'm in 52x19 a lot, 72 gear inches. 17 cog/80 inches when I'm pushing myself, but I can't keep that up for long.
Of course, our OP is in Colorado. I imagine I'd be struggling to get anywhere with a 52/42 setup.