I can only speak from experience
In Idaho, they will speed up the process, or at least they did for us. When my brothers three girls were placed in foster care for the ump-tenth time, My wife and I went to the local CPS. We did the finger and back ground check, we did the home inspection, and took the required CPR classes all within a week period. We were required to do 8 weeks of parenting classes that all foster parents have to take, but they allowed the girls to move in with us before we started the classes because we were family, and took the classes while they lived with us. Maybe each state is different, but it took a total of two weeks before they moved in with us.