There is no perfect answer. After 2 bad experiences,1 so bad the transport guy called me and asked me if I really wanted the car,I no longer buy ANY car I haven't seen and touched in person.
Then again,I am retired,have a diesel pu and 5 ton equipment trailer,and like road trips,so it's not like going in person is some sort of burden.
I even got screwed one time anyway. The car,a 54 Merc was in northwestern PA,and I talked with the guy on the phone,verified the car was still for sale,and told him I would be leaving NC in the morning to come get it and asked him to hold it for me until I could get there,
Got off to a late start so I called him and told him I was leaving right then and wouldn't get there until the next day,and then called him from my motel room north of DC that night to tell him I would see him in the morning. He told me he would be waiting.
Got to his house about 10 the next morning,and the 54 Merc was gone and nobody would answer the door. Which was probably a good thing because it kept me from getting arrested. The SOB finally answered the phone and told me he had sold it to someone else early that morning.
I didn't lose any money down,but I was out over 200 bucks for expenses and 2 days lost out of my life. Given a chance,I would still hurt him today if I could get my hands on him.