There are single family areas in Baltimore, but most of them wouldn’t dare allow duplexes and apartments. I’ll be honest, I’m not a fan of single family zoning. Single family homes pay far less in property taxes per sqft than apartments, duplexes, row homes and towers. Single family zoning also prevents walkable neighborhoods. You can easily find a walkable neighborhood with bars, restaurants, stores, libraries, medical, etc within walking distance, but they’re not going to include single family homes by and large. Baltimore is going to be row home neighborhoods when walkable. There are neighborhoods like that that also have access to trains/public transit and bike lanes. The neighborhoods near Penn Station are probably the best for this mix.