do a pass on the bike unless you like to work on them. Been outside for 5 years?? It is carb'ed. With 66K on the odo means time to look at some things inside the motor. Keep the v star and look in the craigslist, might find a much better deal.
6K is pretty cheap, but it could turn into a lot more in a blink of an eye. It's also possible to spend 75 bucks on fluids, an oil filter, then service it yourself and that could take care of the shifting issue. Add a little wax, some Mother's polish, some elbow grease and all the sudden you have a great deal. If it started easily and ran well other than shifting then maybe hmm... power can be pretty subjective depending on the motor and what's been done to it, I would not be afraid of it soley on the mileage. If your dad knows Harleys, get him to take a look at it or if you have a friend who knows them. I wouldn't just walk away just yet without looking a little closer.
As dwatkins has said be interesting to know what the Evo guys would say about it, gotta say going by the pic it sure looks nice, but as has also been said with the mileage and gear shift could cost you a lot more than 6 grand, any warranty on it ?