personally, if it was me, i would stay and find a location to fortify and ride it out. cause, firstly the previous attempts in season 1 or was it 2? already tried the cdc facility and that was basically no hope. DC would have made attempts to go cdc if there were help.
most likely people in dc would have been over ran and people scavenging like the ricks/gareths/woodsbury.
but like lucified mentioned, for the sake of the show...they have to develop into something. or some new angle for the story to develop into. or else the show run the risk of boring itself to death lol.