The poem is written by William Wordsworth. He is a founding member of the Romantic movement. One of the most important things about Romantic authors is that they loved nature. According to them, nature is good and virtuous; cities are evil and full of vice.
Knowing that little bit about Romanticism helps to break down the title's second half -- "among the untrodden ways." Untrodden means less traveled or less used. Where is something less traveled? Out in the country. Wordsworth and Robert Frost would both agree that the road less traveled is way better. Before even reading the poem, a reader can assume that the poem's speaker is already biased toward liking this "she" because she lives in and among the country where things are more untrodden.
The other significant part of the title is the subject and connected verb. "She dwelt." Translation: she lived. Notice how the verb is in past tense. Why doesn't she dwell there anymore? Did she move away? Was she kidnapped? Is she dead? Those two words, "she dwelt," foreshadow the end of the poem when it is revealed to the reader that in fact she (Lucy) is dead.
The poem's title basically tells readers that the poem is about a dead girl that lived in the country, which is why she is/was awesome.