Congrats on the new bike man!! From the picture, she looks like she will be a good buy. If you are sure THAT is the bike you want, I would not wait, and I would go and pick the bike up A.S.A.P. Research shipping costs first, but if shipping is expensive, you can always drive to TN, rent a ONE-WAY trailer from a U-Haul in TN, and just take the drive. I suggest you ask a friend or parent to take the drive with you if they have the time. Plus, it is pretty cool taking last-minute road trips.
The reason I say pick the bike up A.S.A.P. is because of the following reasons:
1) A handshake is not a legal contract, and he has every right to sell the bike to someone who has the cash in-hand, and who is read to pick the bike up NOW. (people may seem "cool", but when it comes to money, it's always first come, first serve.)
2) If you wait, that gives him more time to ride the bike and possibly change the condition that it is "currently" in. i.e. a) he gets into a wreck between now and August and does not tell you about it. b) He rides the bike and puts more miles on it. etc. etc. etc.
Again, he may seem like he is a good guy, but you don't know him personally, and he does not know you. When you are dealing with that much money, you want to make sure you cover YOUR ass from all angles. I guarantee you he is going to cover HIS ass! Plus, if you go and pick the bike up, you can see the overall condition of the bike BEFORE you fork over the cash.
If going to pick the bike up is not an option for you, send the guy a disposable camera with the return postage paid. Have him use the camera to take pictures of the bike from every possible angle. Those disposable cameras can take anywhere from 14-27 shots. That picture that he put on e-bay could have been taken when he first got the bike, or shortly after.
I know my suggestions may sound like I don't have any trust, but you just have to be careful. Some people don't have any morals, and they will cheat you blind!!
I hope this helps, or at least gives you a few things to think about. Again, from that pic, the bike "seems" to be in good condition. Just be careful.
Good Luck Man, I wish you the best.