. . . If downwind effects are your main worry, I would personally get out of Dodge, especially with young kids. Unlike a full scale nuclear exchange that we all feared during the Cold War, an isolated nuke is going to leave plenty of areas to escape to. There isn't as much need to hunker down for weeks or months nowadays IMHO. . . . And as Chernobyl and Fukushima demonstrate, it's not like these radionuclides that contaminate your area are going to just fizzle and disappear any time soon. The sooner you can leave the affected area, the less damage to you and your family.