I agree with Seneca Pilot. It will take you longer than you think to get to the gate. I live 36 miles away with no traffic it takes me 45 minutes to get to airport, but can take up to 1.5 hours with traffic. The employee bus averages 15 minutes and then 10 minutes to get through terminal / security to the gate. I would monitor Google Maps to see what the travel times look like on a given weekday to give you a better idea.

I've been on DCA FO reserve since September and only received the 2 hour call out twice for extenuating circumstances. The rest were probably 12 hours or more in advance.

Welcome to DCA. Great group of pilots. I've really enjoyed flying out of this base.