I think that any critical appreciation of Frost's poetry has to reside with the reader themselves. Frost's unique ability to take common objects and connect an aspect of human experience to them is what makes his writing so profound and introspective on many levels. With this, critical appreciation becomes something that is geared on the part of the individual. At the same time, I think one could take many aspects of his poetry and apply a critical distillation to it. For example, in "The Road Not Taken," there is an extreme praise of human freedom and action. The speaker in the poem decides to take a path that others have not taken and must come to the fact that this choice has "made all the difference." It is a poem that explores freedom in a unique light because it does not necessarily praise it, but analyzes it as a reality that individuals exercise, helping to differentiate them and provide distinction to their identities. The opening line of the last stanza of telling this narrative "with a sigh" helps to highlight this. The exploration of freedom in many different ways is one element that makes Frost's poem so intricate and rich with thought.
This poem has been discussed over and over again on enotes, so there's a lot of material at your fingertips already.
I would recommend that you use the Search function in the top right corner of the screen and that you review all of the relevant posts in the group on this poem.
Below are two links to get you started.
The inevitable progress of Frost, the poet, is indicated in this poem, which is an often misquoted and misunderstood poem. Once, while travelling alone, Frost had confronted with a fork in the road and had stood undecided which path to take. Finally, he chose the one which seemed to be less frequented.
"Though as for that the passing there
Had worn them really about the same"
He feels that the choice is important because some day he would tell himself that he took the less travelled road.
"I shall be telling this with a sigh/Somewhere, ages and ages hence;/Two roads diverged in a wood, and/ I took the one less travelled by,/And that has made all the difference"
The poet's "difference" is discerned in him from the beginning, long before he set out on his career. He took not only the "different road", but also the best road laid for him. But, the poem had a different purpose to serve when the poet created it. It has a "tongue in cheek" attitude which is clearly perceivable in the hint.
"I shall be telling this with a sigh"--"sigh" which parodies the kind of person whose present life is distorted by nostalgic regrets for the possibilities of the past, who is more concerned with the "road not taken" than with the road taken. The speaker was modelled on the English poet, Edgard Thomas, who after a country war would lament on all the wild flowers that he might have seen on some other road. The negative emphasis in the title(The Road Not Taken), the nostalgic mood, the hesitancy of the decision :-"Though as for that the passing there/ Had worn them really about the same", -the inability to turn his book completely.
The romantic pose finally in the last line:-"And that has made all the difference", all go to prove that the poet's "difference" is in him from the beginning, long before he set out on his career.