Using Scapple to start some sandbox ideas with.
Not sure how well this scales - you've basically got 2 characters and a world there. One you get, 10, 20 characters on 4, 5 worlds it might get pretty unwieldy?
Also, looks like it might get fiddly once characters start moving around.
Seems to me you really want an app that handles the interlinkages for you (some kind of database) rather than one where you have to draw them and redraw them yourself.
That is just the start of a sandbox. When the mindmap is finalized, it'll be imported into a writer and made into an adventure PDF and ebook.