If his primary goal (and I don't think it is) is to make her happy, her goal may have more to do with where she wants to get away from than where she wants to go.
That being said, it seems that anywhere warm and sandy would do just fine.
If he is smart, his primary goal is to go where there is a reasonable chance to make it and where there is the lowest risk. At that point, you spend time to focus on accommodations for her.
The above is my opinion only.
If he was smart, he wouldn't be on the run with a 15-year-old.
However, if he has thought this through, the cleverest way to evade LE would be to leave the immediate area ASAP, lay low for a while, and then move to another location. You wouldn't want to stay in one place for too long, nor risk being caught by being out in the open for any length of time. Unfortunately, they could be anywhere, and we don't have any clues. The only thing we can do is put the word out - everywhere.