I started reading, watching YouTube videos, buying DVD's, and trimming my own horse 2 1/2 years ago. I've put a lot of time and effort into learning. And I've come a long way, but I'm not there yet in terms of being willing to trim someone else's horse for hire.
If I had it to do over, and was learning with the goal of becoming a professional, I would absolutely, one way or another, on bended knee if necessary, set up some training sessions with a well known and competent farrier/trimmer. Salt Lake City?
I'd try to set it up where I could drive the 120 miles once a month for observing/training. If money was an issue, (when is it not?), I'd try to see if at least part of it could be covered by my work (at something).
The thing is, while you or I might see ourselves as helping a farrier, our questions that would obviously come up and the attention the farrier would obviously need to give to us instead of the client and the horse, would impact his work to some obvious degree.
Never-the-less, if the horses in your area need better attention, it may still possible to find a farrier that cares enough about horses to pick out a client that would not mind you being there and observing (just observing).
Good luck in your endeavor. As I'm sure you have surmised, there is just no substitute for a real live breathing horse.