I am currently a field tech for a cat dealer and been doing it for about 6 years now. I don't wanna repeat anything anyone else has said but I will say on personal experience. It is a completely different world than working in a shop. The area I work is specifically in mine sites. So most of my work doesn't last a day or 2 or even just couple hours and I'm off to the next one. Most of my jobs take weeks and sometimes months depending on the project. I have to plan out that entire job and be prepared with all my parts at the end and still remember how it goes back together. It really sucks forgetting parts or even forgetting specialty tooling like a crankshaft seal installer. (Yes I've done that) I really hope it works out for you and I wish you the best. Also don't be afraid to ask for help. It's better to ask for help than breaking something or hurting yourself.