Here is the way that I handle handgun sales out of state:
Make your deal on the EE and exchange all info to include name, address, phone numbers for him and his FFL.
Have him send the funds and copy of his FFL's license (faxed copies are ok)
Take the handgun to your FFL along with the copy of the FFL. Have your FFL ship the handgun to his FFL.
I choose to ship handguns through my FFL as I want to make sure there is a record of the handgun being transferred. In Michigan handguns are registered to the owner and I like to make sure that I have record of it being transferred out of my name. Also by using your FFL to ship, his FFL has all the info he needs to do the transfer to him on his end and it avoids problems with FFL's that will not accept from individuals as well as shippers who give private parties a hard time about shipping handguns.