I have done many out of state sales over the years. Some times you can ship direct to the FFL (Get a copy of the FFL) other times you will need to send FFL to FFL (Still get a copy for your dealer).
Ask for funds in advance usually Postal Money order. I have taken a personal check but I help off on shipping unti lthe check had cleared which can take up to 10 days.
When I ship direct, I use Fed Ex. Use the anytime next day delivery for about $40. If I go through my dealer, it costs more.
I have always allowed three day inspection with return allowed for any reason as long as it is unfired and in the condition I shipped. Shipping both ways is the responsibility of the buyer. This usually makes certain they are returning for a legitimate reason. That said, I have never had a gun returned.
Be honest and above board with descriptions and expectations and you will have no problem.
Regards,