So, over our trip, I rode my mountain bike despite the spine pain, usually spinning the pedals easily on relatively smooth surfaces (getting on the bike was the hardest part). However, if you know me, you won't be surprised to hear that I "cheated" on a few days. On one of those days, I rode to a lookout point that I love, a cliff that requires about 2000' of steep and very rocky climbing to get to it. At the top, you can peer over the cliff's edge down several thousand feet into the deep desert. I adore this spot so much that I'll endure serious back spasms to get there.
Being out in such a peaceful place with my pack certainly helped!