As Twisted said, remove plugs, don't use fuel, but turn the motor over after drizzling some penetrating or motor oil into the cylinders.
I'd strongly discourage using nuts and bolts in a gas tank to aide in de-rusting. Sure, they aide in "scuffin" but they can be a M-F'er to get out. If you DO put something metallic inside, use a length of regular chain, or even a bike chain. Grab one end, the whole thing comes out. But most chemical baths (vinegar included) don't need the agitation to remove rust.
Also, remove the battery from the bike, and attempt to charge it with a motorcycle charger. It's probably shot, but might still work. Do NOT jump the bike from a running car, this will do lots of damage.
Locate the manual (found elsewhere on this site) and perform the 3,000 mile service interval. This will aide you in determine the condition of the bike and identify and real major issues.