Like rowhard said, VX Kat (Sue) has put together a pretty comprehensive list of things to look for/ask about the VX. You may also want to ask if any other members are in that neck of the woods. Many of us have checked VX's out for members, and have had VX's checked out for us. I found mine in Chicago (I'm in Colorado) and had a couple of local members check it out for me before I flew out to see it myself.
If, or should I say "when", you do buy it be sure to check the oil religiously on the drive back home to get a gauge for how much oil (if any) it burns.
Good luck.
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-Douglas Adams, Mostly Harmless