She got the best prize of all the companions.
When people look into the heart of the TARDIS it's like it grants wishes, or rather it does grant wishes.
And all of the events had led up to this moment, which was this;
Her father and mother alive, a financially secure home, and best of all a Doctor to spend the rest of her life with AND Vice-Versa. Not to mention they have a Parallel Universe Torchwood with all the knowledge of a Time Lord as recourses to build their own TARDIS.
And continue to have adventures until the day they die. And then have their children go on crazy adventures.