I wonder what was going on in her life that made her say, "I want to spend the next 43 days rowing alone across the ocean."
She spent 41 days making the same trip with 2 other people
This is one of those cases where getting started is hard, but once you get started you probably can do more if you want it because you get a reputation and people will sponsor you. You end up in a lot of cases your job is to get sponsors for this trip and you live in the meantime cheaply just earn enough money that you can afford to take off a couple months to do these things.
That said, it probably isn't all that expensive. You do need to get a canoe, but those are not terribly expensive. You need enough food to last this long. The ideal way is if you're living with your parents or some other situation where you can just stop paying rent while you're on the trip. A large part of living expenses are things that she would not have when she's out on the ocean. Also, if th if this is your goal you're probably living for that so you might be working two jobs to raise money for the trip and then you quit both jobs, take your trip and then you go back to work.
https://en.wikipedia.org/wiki/George_Mallory
Some people are just driven to do things for the accomplishment. I don't think we need more psychologizing than that.
But that which obviously means the most from the standpoint of fulfillment :)