If ordering from catalog works, still doesn't change the fact she is random =) I have her appear so frequently in 2 weeks but some said she appear 2 months after the last time she show up. So use some tricks. I heard if she appear in your town eg: today. After pass the check, turn your in-game clock back to 6am (the same date) and she will appear again in your plaza, so you can complete all 4 checks in one day =)