I haven't checked in for a while so I just saw this- I had a N.J. FFL from around 2000 to 2007. I pursued it under "gunsmithing" instead of firearms retailer.
I was able to get the state and federal licenses, most likely due my "access" to the system. Without knowing some of the bureaucrats in my jurisdiction and a few of the njsp firearms unit guys it would have been a very long process.
Not to mention, if you are going to 'smith, you are going to have to test fire- not something you can do in a townhouse.
Both in N.J. and in now in Pa. I am blessed with understanding neighbors that tolerate the gunfire (I test fire indoors, into a proper trap).
It's probably better to work under the FFL of one of the shops you work for- unless the law has changed, you already have the "pink card" that allows you to work behind the counter at a gun store.
I'll also throw out there that gunsmithing will NOT generate enough revenue to keep you in hookers and blow...
-Sean