First, check to see if the PO has a maintenance log. That will tell you how much care was given and the date of the change.
Second, make sure you get to ride it. Listen for noises when idling and when under way.
Third, check for wheel bearing wear by placing the bike on main stand and spin the rear tire looking for side-to-side wobble. Next shake the rear wheel side-to-side and again check for looseness. The front wheel can be checked for looseness to same way.
Check that all the lights (tail, turn, brake, head, dashboard) are working.
If equipped, the ABS light will turn off after the bike reaches around six mph. If it stays on after riding, there maybe something wrong with the Antilock Braking System.
Good luck! Make sure you come back with a status update!