i need urgent help...i dont get the meaning of this sentence"i go and come with a strange liberty in Nature,a part of herself"

go to google books; title of book is "This Incomparable Land: A Guide to American Nature Writing," and scroll down to page 78. I already provided you the link in your last question.

What he's describing here is solitude; physical and mental isolation from everything except the nature he's surrounded by. He's become at one with his surroundings; his mind is free from all other thoughts, ponderings, and worried. Nothing exists except the time and place he's experiencing. This is what Thoreau is feeling in this section.