Recommendations for bicycling in Cambridge, MA cheap?

Guys, I'm going to Cambridge for a conference and staying a few miles from the hotel. My per diem rate would cover the cost of renting a road bike daily, or, looks like some of the road bikes on Craigslist. How secure do I have to be (take front wheel of and lock frame and both wheels? Or more?) What about commuting from my hotel north of the river (a bit east of MIT) to the Harvard School of Public Health? Doable?