Sounds like a dream opportunity. Up here, it's hard to get anything that lasts more than a week or 2. Messing with CNC programs & setups is usually pretty easy until you get into 5-axis. G-code was developed in the 60's & 70's to make it easier for machinists to interact with the computer for consistent, good & efficient operation. Mazatrol & the like is equivalent, but more flexible and evolving to potential for obsoleting g-code. Just be very careful with your alphanumeric characters that look alike (0 & O), punctuation & rapid moves. The rest is common sense & remembering obscure commands specific to canned cycles & functions between brands.