Just remember that there has to be reward tickets available on the flights that she wants...

2) Paying for miles is not really a good idea...The $450 would also be in addition to the implied value of 10500 miles currently in possesion.

3) There are also other sundry benefits available to Amex Platinum card holders that she would get


In conclusion, I don't often recommend the Amex AP Platinum to people because of the high annual fee, but it sounds like she would be one of the few people that would greatly benefit from it (at least for the first year).

Just make sure to cancel/reapply for it after 12 months