$250+tax Replace Playfield
$280+tax Replace Rod Set
Given these two figures alone... Someone will probably buy it for more than $400
I'm just thinking your discourse about the table's condition and any upgraded parts can help you learn some more about the table's valuation and make a decision to drive and buy it. $600 is a tiny bit high in my opinion if it is stock with older figures but that is what I would list it at if in good working condition, yet I would expect to sell it at $550ish. You are not the only one in his market so I doubt he'll go for $400. I'd say offer $525 with old figures, $600 with new figures, assuming it is in excellent shape.
Buying a random used table over a long distance is a huge hassle and risk. I have bought 2 this way and each time was a gamble. Usually tables are not setup correctly and hard to assess. I drove 3hrs and 2hrs for both of mine and even though I checked everything recommended I should have tapped the ball around the sidewalls on my brown marble.... loose laminate snap here and there.... In hindsite, I did ok, but I should have valued my gas and time as well. Both cases add about $300 onto the purchase price. Most good tables are passed between friends, the public gets the leftovers....
On an optimistic note, buying the tornado coin gives you basic security even if you miss something... parts, support, and advice are easy to track down as the design has been static for a looooong time.