I know of no such laws. The laws that I do know of which prohibit criminal activity in connection with crossing state lines are federal laws.
In this specific case, if a state saw the fetus as a person and abortion as murder, it would be a short step to argue that taking "a person" across state lines (or, actually, anywhere) against their will would be kidnapping, and that anybody who helped in any way is part of a criminal conspiracy. Don't be so sure it couldn't happen.