Techshop is really cool, but the different locaitons seem to have different offerings, but many overlap.
There is also such a thing called a hackerspace. According to this map, there are 4 in your area. http://hackerspaces.org/wiki/List_of_Hacker_Spaces The general premise is that they are communal places for people to work on projects with whatever tools are available in the space. They are all probably going to be different, but with 4 semi-close by, you probably have some pretty good options.
For G-code, youtube. Seriously, it's crazy dry stuff, but I learned a lot of it on videos about MACH3, which is the program I was going to be using. For CAM, an embedded program is probably the easiest. HSMexpress is free and has options in Inventor and Solidworks. There are tutorials, and learning within a CAD interface you know is always easier. Any specific issues, throw it into Google and see what pops up. Watching demo videos on YT, again, is another way to learn the CAM side if you prefer like that.
The only G-code I really know and feel the need to use is G54 of G53 to tell the machine where to go. I could just jog, but if I jog it to get a new tool in, I can just tell it to go G53 X0 Y0, and now it's back to the machine's XY zero.
I've brought problems here too, and had quality help in a few hours. Sometimes, a second set of eyes is all you need.