Tho it's a long ways away, for students who picked the Marine option after the academy, how was the process? The whole process; camp leatherneck everything? Also can you go into specifics on the TBS humps that's all I'm really worried about.
I am not an Academy grad so I can't speak to the process that gets you to TBS. The "nature walks" at TBS are nothing to worry about. You have plenty of time to learn how to carry a load and build up your endurance. Google "USMC TBS humps" or something similar and there are a lot of blogs and information on what to expect and how to prepare. For instance: http://officercandidatesschool.com/blog/2012/09/21/nine-tips-for-marine-corps-humps/
Humps will vary in length, load and intensity. They are used for PT, conditioning, assessing, team building and necessity (getting from point to point).
If you have never backpacked as a civilian, you can start now and learn how to load your pack, wear it properly, proper boot fit, care of the feet etc.
After TBS DD said she knew every tree and stream at Quantico. She had run into or fallen into every one of them on night training as did every one else both male and female. Leatherneck during the Academy years is almost a given for selecting Marine Corps. I think Marine Cadre at USNA evaluates each person selecting Marine option. Checking USMC TBS would be a good start for information.