Kevin,
Congrats on getting the job! Nice work. Sounds like they see your interest and passion for the job, and that you are willing to work to prove it. Just like you mentioned, there will be a myriad of things they may ask you to do - just the way it is on a tourist railroad. I did the same; offered to do anything I could to help out, and learned all I could.
When you do start working, post a couple messages about what your up to. Its always interesting to hear and see what us young guys are up to in the steam world.
Shane Schabow
Former GLRR Inc. student trainman/locomotive fireman