A gadabout is a person who gads about. Obvious when you think about it, isn't it? Well, that's unless you're not entirely sure what gadding about involves. Fortunately I'm a gadabout myself (even when writing my books) and therefore able to enlighten you.
To gad is to go about in search of pleasure, or idle wandering and adventure. A person doing this can be said to be 'on the gad'. I have gadded on numerous occasions.
After writing it in all it's forms, I'm no longer sure I like the word gadabout and would rather you thought of me as the travelling writer.