I'm a social worker that loves to travel but likes to do it cheap, and to hang with local folks. Typically, I've done this utilizing the youth hostel network but have heard good things about airbnb.
I typically travel with my mother. We get along well and make good travel buddies - we're adventurous and curious in different ways. We love walking local neighborhoods, checking out farmers markets, visiting street festivals - whatever makes a community. I'm a low-maintenance traveler and house guest. Honestly, since I'm a social worker in high intensity situations, I often prefer to participate in community, without lots of direct social interaction, when I take vacation. Social, from a distance!
For folks traveling to Baltimore - I love sharing the lowdown about my adopted city. It's a fun, funky place with lots to see and do. If you run out of stuff in town, DC is only an hour south, Philly and NY just a few hours north. All are easily accessible via cheap mass transit.