you can leave your game any time the oldman will visit you with in those three days but you must not be in any major city like coronet-corellia, theed-naboo, you will have a better chance of meeting the oldman if you travel to player city's that were formed by guilds, also if you are currently in combat or doing missions the oldman wont come. Once I landed in a player city it was about 10 minutes then the oldman came but he came to me and when I tried to converse with him he turned and walked away so I just logged out real fast and logged back in then he came again in 5 minutes gave me the crystal and and he left, then about 10 minutes later the sith cought up with me I killed then (novice pistoleer) easy to kill.