Last Light by Terri Blackstock -- 400 pages
The family is going to have to work together and shoulder hard responsibility in order to survive, but they have split motives. Deni just wants to get back to Washington D.C. to her fiance, but there's no way to do that now. She's stuck in a tiny, hick town. Even worse, there's a murderer and thief about.
This is book 1 of the Restoration series.