Okay, so just FFL meetup with the other party - they run the instacheck and cash and carry?
There are 2 exceptions to this:
1. Muzzleloading firearms.
2. Antique firearms (manufactured 12/31/1898, or earlier.)
These are exempt from federal regulations regarding interstate transfers (state regulations still may apply.)
These probably don't apply in your particular situation, but I thought it might be worth mentioning anyway.
3. and C&R guns with a FFL03