Symbolism, Imagery, Allegory
There's only one road in Avonlea, so if any character's climbing into a horse and buggy, they're either travelling far enough either to visit the world beyond Avonlea or to return home—both exciting drives full of beautiful Prince Edward Island scenery.
The most epic of which is, of course, Anne's first journey home from the train station with Matthew. That's when we first meet Anne and the world she's about to enter, viewing the scenery through Anne's first-time eyes.
She calls a road Matthew has travelled many times,
"[…] the first thing I ever saw that couldn't be improved on my the imagination." (2.53)
It gives us a sense of the intense beauty and of Anne's excitement for what's coming.
Both the anticipation of adventure and the comfort of the landscape are emotions that go along with the road.