Welcome, Scott!!! I live in GA. I never met Mr McCormick, but my father, Melvin Tucker used to build mandolins and knew who he was! What's interesting is, that I was over in Alabama earlier this year, meeting a client at a guitar shop (to which the shop owner had agreed we could do). The client picked up his guitar, as did everyone working at the shop. The owner of the shop said he had a guitar he wanted me to see, which was built by a gentleman who did repair work for them, and had recently passed away. He brought out a parlor size guitar apparently made several years ago, made by Mac McCormick!!! The owner of the shop spoke very highly of him. I just thought I would share that with you, as he seemed to be quite respected by those guys!
Dad hasn't built but 2 mandos in the last year, and more or less got out of it several years ago. I know how you feel regarding following in family's footsteps, as I am sort of doing the same thing (trying to anyhow!). I have been enjoying the guitars so much that I have not really fooled with mandos yet. And I ain't quittin' my day job!
As far as advice, that's a tough one. How much experience do you have regarding woodworking, fine furniture, eye for detail, etc? If you have a woodworking background, I feel it's a plus in my opinion, but not an absolute. Some folks here have built with little prior woodworking experience. If you do not have availability to good builders in the area, some good books are out there, and the internet can be a great source. Neither should be considered absolute sources of perfect information. Cumpiano's book, although a little dated now, is a good book for basic techniques on construction. Some of the techniques in the book have been replaced by more modern approaches, but a great guitar can be built with the book. He uses a dread and a classical as his examples.
For more modern techniques, and good ones at that, consider some of the sponsors here on the OLF, along with some of the advice given here on the forum. There are kit guitars out there, some available by sponsors here. It may be advantageous to give one a try. Acquiring tools specific to building can get as expensive as you like!
A word of warning....building is in your bloodline!!!! Danger Will Robinson!!! GBS (guitar building syndrome) is an addiction hard to shake!!!!
If you ever do come to GA, stop by!
Brad