Yes you do, the Huayna Picchu entrance is the only access.
Which hike is harder? Machu Picchu Mountain or Huayna Mountain?
I have not done either of these but from what I have Heard from past guests (a few have done both), they are similar in difficulty, Huayna Picchu is steeper tan Machu Picchu Mountain, but it is also shorter making the overall physical exertion about the same, again this is just what I have been told.
-:- Message from TripAdvisor staff -:-
This topic has been closed to new posts due to inactivity. We hope you'll join the conversation by posting to an open topic or starting a new one.
To review the TripAdvisor Forums Posting Guidelines, please follow this link: http://www.tripadvisor.com/pages/forums_posting_guidelines.html
We remove posts that do not follow our posting guidelines, and we reserve the right to remove any post for any reason.