Concept: Great idea, I especially like the focus of the “Stanford campus.” It might be a good idea to say something on the front page about how the website is uniquely designed for Stanford students, rather than just saying “at Stanford” at the end.

Audience: I think the “working out” audience, is very large, as is the span of ages as Stanford. It might be a good idea to break down the audience as far as age group, different trails and exercises might be better geared towards a particular age group, or a particular gender.

Project plan: Your business plan looks good. I think that your marketing plan in particular will work out quite well. You may also be able to include hiking trails etc. nearby the Stanford campus, which if privately owned, could give you money for advertising.

Site organization: Right now, it seems like the site will be fairly easy to organize, with separations made at running, swimming and weight training. However, there might be too much information on each of these topics to keep them at one page only. As mentioned earlier, you will have and audience of varying skill level, age, and goals. It might be good to provide links to a different part of the page, or a subset of the page in order to keep readers from getting frustrated when information does not directly pertain to them.

Ethics/Potential risks/problems: I think you’ve covered this in your disclaimer quite well.

As a side note, I think multimedia would be a really good thing for your site, whether it's a small tour of the gym, or a clip demonstrating good technique. One of the main reasons people go to exercise classes and have person trainers is because they are shown exactly what to do. I think for your site to be successful, you need to have some sort of visual component.