we meet at the local gun shop that has a range, high traffic volume and most people in the parking lot are armed in some fashion so I feel pretty safe doing the transaction there, plus I have someone go with me that's armed as well.
I guess I'm just too much of a trusting soul. I guess I have bought or sold two dozen or more in the last five or six years to people who just came to my house, looked the gun(s) over, paid, and went on their way. At least a couple of folks rode with me in the golf cart to the back yard range and tried out the gun. Usually, we just meet in a parking lot in a fairly public place. I have never, ever had second thoughts about personal safety, or felt uncomfortable during one of these transactions. I have met some very interesting people, too.