Get her used to the travel cage first, I think. Mallorn, my hen, is very, very skittish when it comes to new anything--toys, fruits or veggies, cages-- and the only way to get her to accept it is to show her that it's okay. I would start doing this now: get the travel cage and put it by her regular cage. Put toys and millet in it, and touch it or play with it a lot to show her that it's okay. When you let her out to play, make sure she can see the cage.
It will take a few times, but eventually she will just start going in and out of it like a playgym.
Hopefully she realizes that it's not going to hurt her and then when it's time to go it will be easier to put her in
Good luck, hope your vacation is a success!