ATL-IAD isn't that bad of a commute at all, even with Air Tran pulling out. Worst case scenario you go to DCA (which I've only done once due to a cancelled flight) and hop over to IAD via the metro and Washington flyer bus. $6-7, cheap stuff. Good deals on hotels can be had too. I'd say on average if I get a hotel, the price out the door is around $65 or so.