It means that there was a a provisional plan for her to travel to Aruba (which probably did not happen - although we don't have the rest of the story in your sentence...)
You could replace this with:
- Her intention was to travel to Aruba.
- I understood that she planned to go to Aruba.
- She said she intended to go to Aruba.
However, this plan was not very concrete. This is indicated by the use of "kinda" = kind of = sort of...
"Supposed to" indicates an assumption:
He is supposed to come to dinner tomorrow = he has been invited but I am not sure where the he will actually come. (Or: He said he would come, but he is not a very reliable person, so I'm not certain that he will come...