The BWI area (airport) is a popular spot for ladies. It's better than having to deal with parking issues than the city of Baltimore and there are many hotels that are literally a few minutes from the airport and most have free shuttles to and from.

It's also not very far from DC (30-40 minutes) although the way some guys are that's like driving to Florida.  

Columbia or Arundel Mills.  They're a bit further from the airport, but parking is easy and there's a decent selection of 3 star places to stay.  
The Inner Harbour is nice to... more upscale hotel choices.  Parking can be a bitch (but nowhere near as bad as parking in DC - LOL)
give me a shout if you have any "sensitive" questions. I'll be happy to dish

It is centrally located and easy access for all.  Lots of affordable locations for stay and meals.  You could also stay at the hotel/casino that is physically attached to a large mall for shopping and food options.  Please feel free to ask for any specifics.  I am sure people would love to see you in the area.