I live in Annapolis, MD but every now and then I'll be in the Baltimore area and decide to stop by here. The parking sucks and I'd suggest you park in a garage rather than chance getting towed. Be sure to take your parking slip in with you as u can get some vendors to validate it for you for $2 off. Be careful navigating through the crowds- I've seen pick pocketers. There are always crazy folk stumbling around and people begging for money. I hate that!
As far as the food there, I go there for gizzards and livers mixed with ketchup and hot sauce and since you're in Baltimore you might as well go for the half and half. It's half lemonade half iced tea. It's been a mainstay in Baltimore for as long as I can remember it. I sometimes enjoy getting the chitterlings there too with vinegar and hot sauce - gotta have the hot sauce- and potato salad. My mom loves that year round you can go there and get bags of christmas candy. It's definitely an experience going there and clothing stores across the street are really cheap and trendy too.