BigBlueToe

I'd say there are two pretty-much necessities. If they're covered, her bike should work fine. One is a wheelset that won't break spokes. I'm 6'4", weigh 205, and typically carry a big load. I've broken spokes on tour and it's definitely a drag. Your friend undoubtedly weighs less and her gear is likely also lighter. Her wheels won't need to be as strong as mine, but if they're not up to the task and spokes break, she'll be sorry. I suggest having a rear wheel built by someone who knows about the rigors of touring.

The other necessity is a gear ratio low enough to climb steep, long hills with a load in relative ease. Can she install a wide range cassette and a triple crankset with a low granny?

If she can pedal her load up the hills without too much discomfort, and if she can get through the tour without breaking anything, she should be quite happy with her Fuji. If not, she likely won't.

Maybe if she considers these things (among others) she'll see the advisability of a better tourer. I'm wondering if her love for the ride of her Fuji has to do with the fact that she's got the fit dialed in. I'm guessing if she buys a new bike and tweaks the fit she can be just as happy if not happier with the ride. I love my LHT's ride with a load, but it's different than my old tourer and took a little getting used to. After I got my new Allez, I didn't like the LHT's ride quite as much in comparison, but I certainly wouldn't want to try the Allez with a touring load.

Ultimately, though, I agree with those who say it must be her decision. My wife and daughter were both happier with their bikes when they got to have the final say. They liked to listen to my advice, but wouldn't want me making their choices for them.