If you are not running a business, zoning should not affect you (some museums have an 03).
The licensed premises are where the guns and the paperwork should be.
You will need to maintain a "bound volume" of firearms you acquire and dispose of. Guns in, guns out. Pretty simple really.
Yes, you are subject to inspection by the ATF. Once a year. Most of us have never been inspected, and if you are not selling a bunch of guns, not likely that you will be. An 03 has the option of having the inspection done at an office designated by the ATF- you can take your guns and bound volume to them.
Go to the ATF website and do some reading.
A few states (CA, NY, NJ) will treat C&R handguns differently. You will also find that there are a number of wholesalers you can buy from, places like Numrich and Brownell's will give you a discount on their stuff, and you will encounter 01 Dealers that do not know what an 03 is.
PS- You still cannot MAIL a handgun by US Mail. Limited to Dealers and Manufacturers.
What we have here is... failure- to communicate.