225 is a great deal, especially if the monitor and bd are in good shape. If it were me, I'd take it in a minute for that, even if the monitor needed a cap kit. I've successfully installed a cap kit and brought a vector back to life, and if I can do it, anyone can!
As I recall, the G05-805 is the 15" b/w vector used in the cocktails (it's the G08 color that tends to self-combust), or it could be the WG 15v2000. Either way, I don't think much of a fire hazard, just a shock hazard.
I also recall seeing one of these at an auction recently and thinking how much it lost without the backdrop, etc, which is not on the cocktail. I believe that the vectors in the upright are overlayed on the background via a half-silvered mirror, like in Warrior. Therefore, I don't see any easy way to effectively recreate the asteroid field in the cocktail. That said, I always liked AD better than Asteroids (at least you could use the shield, as opposed to the hyperspace) and would gladly add even the cocktail for that price. Good luck!