Individuals like you amaze and inspire me, the ability to run fast BQ times and run ultras, incredible. I don't think I have the discipline to run a Boston time, but pushing along for a day+ out on trail is a joy, sign me up.
The tinkering associated with backpacking is almost nonexistent in running, at least for me. Its easy to keep running simple if you want it. My only weakness is shoes, the searching, learning, and continual evolution of shoes, its a cycle and I never seem satisfied for long. During periods of training I get a bit obsessive and my vision narrows.
One thing is for sure, backpacking is literally a walk in the park once you start putting in long miles on trail with elevation thrown in, makes cranking out 20+ mile hiking days a breeze and quite enjoyable.....pair that with a light pack?