We did it!
I couldn't believe how teary I got when we got to the top - it was such an accomplishment and I felt really good! All of the hours and miles of "boot camp" paid off. The views were fantastic all along, and we again had gorgeous clear skies all the way to lunch. We got to see some more wild viscachas lounging in the sun on the rocks, once we got up to their preferred altitude (> 14,000 ft).
We're now at our lodge for the night, after hiking 8 miles today, and we "only" have 6 to hike for all of tomorrow.