Hi! I went to JHU undergrad, lived off-campus, and stayed in the area for several years after graduating. I can tell you that the areas around Homewood are relatively safe, but you have to keep in mind that it is an urban area, so you need to be street-smart. Stay in lit areas and carry mace. There's a JHU shuttle that will take you anywhere within a mile of campus - definitely use it at night - and a regular route shuttle that hits the grocery stores, so you can easily manage w/o a car (not than anyone asked).
Definitely avoid the Marylander. Bad management and cranky neighbors, thin walls. But they used to have a good deli on the main floor - don't know if it's still there or not. Carlysle is a good building, but small, hard to get into; lots of student live in the Broadview, it's worth checking out.
But don't forget the rowhouse option! There are TONS of rowhouses in CV; some are split into apartments, but if you have friends you can rent a whole house. I would also suggest checking out Mt. Vernon, which is just a little south of campus (where Peabody is). There's two JHU shuttle stops, one to Homewood and one to the med school; they pick up every half hour. Great neighborhood.
Def. check out Craigslist (I wish we had that when I was in undergrad), and I think the Baltimore City Paper might have listings as well. And a lot of cool apartments in row houses won't even be listed anywhere - you just have to drive around and look for "For Rent" signs in the window.
But don't worry, there's lots of housing to be found, and you can easily find affordable housing.
