Yep. Almost all of the flying is out of IAD but there's a few flights out of DCA and BWI. As far as I remember (it's been quite a while), all DCA and BWI flying has the same crews flying in and out of those cities - in other words, I don't think that any trips originate or terminate in DCA or BWI.

However, my caution - there are times where 1) the FO gets sick, which is why you're covering those bases, and 2) when they're very short on crews, they'll piece together trips with multiple crews.

I've gone one way between IAD and DCA very easily with public transportation. I've gone one way between IAD and BWI (both ways) by renting a cheap one way rental car - I don't know how easy that will be to find, but you can check. And ask in the chief pilot's office how they'd recommend getting to/from BWI.

As far as the short call, let's hope that crew scheduling gives you a reasonable amount of time to get there. If you can't make it when they tell you they need you, just say, 'I'll do my best to get there at that time'.