Based on his introductory note, who is Geoffrey Crayon?
Geoffrey Crayon was actually a pen name for the real author, Washington Irving, and we must consider the character of Geoffrey Crayon in this context. No small part of this is the fact that Irving was living in England, and published Sketch Book simultaneously in Europe and America; this led to his works being among the first popularized American literature. As a character, Crayon needed to avoid appearing as too much of an American cliche, nor as too much of the typical European young gentleman. He is a little of both; a young American with a frontier spirit, but the humility to recognize Europe as his heritage and a "giant" in whose shadow he stands.
The book begins with a quote, which we may assume applies to Crayon though it is not said by him, which mentions having "neither wife nor children, good or bad", and being an observer of mankind. Crayon then gives a brief expository on himself and a background that partially serves to explain how he came to acquire such a variety of stories. This is a narrative common to literature of the period, such as Frankenstein. Crayon explains that he has always been a traveler, even as a young boy, and when he essentially ran out of places to explore in his area, he thought of going to Europe.
Thus we may assume that Crayon is a young bachelor, probably with at least some amount of money and no real need to work, and an insatiable curiosity about people, places and the stories associated with them.