Which lines from Guthrie’s song "This Land Is Your Land" were most likely inspired by this aspect of his life?

I saw above me that endless skyway:
I saw below me that golden valley:
And the wheat fields waving and the dust clouds rolling,
As the fog was lifting a voice was chanting:
As they stood there hungry, I stood there asking
Is this land made for you and me?
Nobody living can ever stop me,
As I go walking that freedom highway;