Look for cracking on all visible hoses. Check age of the tires, there is a code on the sidewall you can reference from the MFG to determine tire age. If they're more than 3 years old, doesn't necessarily mean you need to replace them, just don't ride it like you stole it with old tires.
IIRC that generation of Multi used the safety return cable throttle by wire system, where the throttle was opened via servo, but the closing was still manually actuated. Check the single cable for abnormal wear or lack of lubrication.
Pull the dust covers down on the fork tubes and bounce the suspension a few times, look for oil on the tubes, fork seals degrade over time.
Insist on seeing the bike start from cold. This is always good advice with a used bike purchase. A little bit of smoke from the exhaust on a cold start isn't a terrible sign, if it stops quickly. Shouldn't last more than 30 seconds or so, if it does you'll need a mechanic to tell you why, can be many causes, some serious, others not.
The '10-12 Multis were somewhat known for electrical gremlins. Not all of them had problems, but if one did, you might imagine it not being ridden much. Not much way to test for that beyond a long test ride, which I would insist upon, given the age, mileage, and price.