HI,

I went to Harvard as an undergrad 10 years ago and now live literally five blocks from Harvard Square. If you only want to walk to Harvard, your choices are the Inn at Harvard, the Charles Hotel and the Sheraton Commander. The first two are literally right there and the Sheraton is halfway between Harvard Yard and the "Quad" where some undergrads live, still only a five minute walk from the Yard. They are all nice hotels. The Charles is probably my favorite and has a great (and very popular) brunch on the weekends at Henrietta's Table. Anything else will be a bit annoying if you are going to be there for two weeks. The hotels in Kendall Square (the Marriott, Residence Inn, etc) are two "T" (subway) stops away but Kendall is otherwise quite boring and the T shuts down at 12:30 at night so you might find yourself a bit limited. If a kitchenette is not absolutely a must, there are plenty of cheap places to eat in the square. Remember that it caters to students, i.e. people with no money.

Border Cafe at the corner of Palmer and Church Streets in the middle of Harvard Square is arguably the most popular place to eat for students (tex-mex).

Good luck. Harvard is generally extremely safe and there will be people walking around until quite late, with plenty of Cambridge cops and Harvard security around regardless.

p.s. Do not stay at the Doubletree. The walk is too dangerous as you have to cross a very busy road and walk across the bridge to get to the Square.