Sounds like you are both benefiting from working with that friend. I agree that making a record of what you are doing is helpful for you in the future and to everyone who reads it at any time.
I certainly think so.
As a kid, all the benefit was in the running of the trains. As an adult, I have a much greater appreciation for the social aspects of the hobby. Going to train shows with friends, talking and seeing my forum friends, participating in NMRA clinics, and having train operation sessions all contribute to the enjoyment of the hobby.
Doesn't hurt to have people with diverse and superior skill sets looking over your shoulder, either!
Guess it's true: as ye sow, so shall ye reap.
George