It wasn't three hours away, and it wasn't a bike I was buying, but it sure sucked when I arrived and heard, "Oh, I thought you weren't coming, .... I just sold it, Sorry." Almost as bad was showing up and they weren't there, or the time they were there, but "Dang, where did I put that generator? I thought it was in the shed. Follow me across town, it must be at my parent's place."
This is why now, I try to get the seller to put some skin in the game. Having them meet you 1/2 way, or 1/4 of the way, or anyplace other than their home is a good start towards ensuring they will actually be there with the goods, somewhere near the designated time. This also doesn't hurt with the negotiations. Asking for pictures of everything, and repeating the phrase, "I'm driving a long way, and I don't want to be disappointed" doesn't hurt either.
Of course, if you have been searching for the holy grail, and they are giving it away for next to nothing, you just jump in the truck and get there as fast as you can.