That's feasible to do for sure. LP Steamers or Nick's would be my suggestions to get crabs, and I think both are very easy and cheap to get to by Uber from Camden Yards. Only suggestion would be that getting to and from Camden/Penn Station would be cheaper if you took the light rail. You can wait for the Light rail shuttle that operates between Camden and Penn every 30 minutes, or the better option imo, would be to walk like 5-10 minutes around the corner and catch the more frequent light rail at Mt Royal.