This is a very pertinent question, because the truth of the matter is that Hawthorne manages to create a real sense of ambiguity over the travels of Goodman Brown into the woods. We are never really sure what is real and what is fantasy, just a dream that he had, and the way in which the narrator himself asks this serves to make us unsure of deciding either way. Note the rhetorical question that is asked at the end of the story:
Had Goodman Brown fallen asleep in th forest, and only dreamed a wild dream of a witch-meeting?
So, it is very hard for us to distinguish fact from fiction in this tale. Having said this though, there are definitely elements of fantasy in the account that we are given of what happened. Certainly, one place to start would be with the gentleman that accompanies Goodman Brown and the way that his staff is described:
But the only thing about him that could be fixed upon as remarkable was his staff, which bore the likeness of a grat black snake, so curiously wrought that it might almost be seen to twist and wriggle itself like a living serpent.
Note how later on this staff is suggested to have transformed itself into a snake when the gentleman throws it to Goody Cloyse. In addition, you might like to look at how the meeting is described that Goodman Brown spies upon, and in particular the "music" he hears coming from it as he approaches:
The verse died heavily away, and was lengthened by a chors, not of human voices, but of all the sounds of the benighted wilderness pealing in awful harmony together.
Such accounts obviously add a fantastical element to the tale, but, as I previously mentioned, we are never able to prove that Goodman Brown's adventure in the woods happened factually or whether it was just a dream.
An interesting question, especially since some Early American Literature relies heavily on religion in writing (consider the Quaker/Puritan names used in the story: Faith, Goody and Goodman). Hawthorne would have known the Puritans strongly belived in their religion's potential to transform and glorify. He certainly plays with these elements, but also allows for the fantastical, which adds to that ambiguity which makes the story so interesting.
What he also would have know is the nefarious past of his birthtown Salem, NH. Famous for the Salem Witch Trials and persecution of the Quakers, part of his upbringing is surrounded in history, much of which shaped his writing. So, yes, in a sense Young Goodman Brown contains elements of fantasy (and romance).
To prove my point, let's look at a few examples from the short story.
-Think of the setting: the woods, both gloomy and foreboding. Brown is at a witches' sabbath deep in the forest of 17th century MA (a big no-no in the Puritan/Quaker religion). Hawthorne also plays with sound, distorting the natural forest 'music' into something unnatural and creepy. By the same token Hawthorne intorduces elements of the gothic by again distorting images of the forest (trees, clouds). The clouds 'babble,' he sees Faith's pink ribbon and
- Brown's state of mind could be considered delusional and slightly prone to fantasy (I mean, who can honestly say they've seen the Devil). And, to have the Devil tell you in honest conversation that your family once practicted the black arts might be slightly disconcerting.
- The surreal nature of time passing (and changing).
- Hawthorne plays with the idea of spirit-inhabited forests, ghosts (in the form of the Devil and his absent wife), secret meetings, terryifying and mysterious sounds and really the creation of a world in which nothing is as it seems.
If you're interested in pursuing the fantasy idea, I'd also recommend you look into the idea of Gothic. Hope that helps.