In general, you are able to travel with your children as long as it does not interfere with the other parent's custody time.
In Nevada, custody orders should come with the standard notification that:
PENALTY FOR VIOLATION OF ORDER: THE ABDUCTION, CONCEALMENT OR DETENTION OF A CHILD IN VIOLATION OF THIS ORDER IS PUNUSHABLE AS A CATEGORY D FELONY AS PROVIDED IN NRS 193.130. NRS 200.359 provides that every person having a limited right of custody to a child or any parent having no right of custody to the child who willfully detains, conceals or removes the child from a parent, guardian or other person having lawful custody or a right of visitation of the child in violation of an order of the court, or removes the child from the jurisdiction of the court without the consent of either the court or all persons who have the right to custody or visitation is subject to being punished for a category D felony as provided in NRS 193.130.
Despite this stern warning, if it is your custody time, you are not in violation if you are not interfering with the other parent's custody.
Sometimes, usually when a parent has a history of abducting the child, a court might prohibit removing the child from an area in another order. But this is rare. In almost all cases, a parent can travel with the children during his or her custody time.
This is true only for travelling within the United States. If you want to take children outside the country, you will need written (and usually notarized) permission from the other parent or an express court order allowing you to do so.
Also be careful if the child will be missing school: custody orders often prevent travel that would cause a child to miss school without both parents' permission.
Finally, many custody orders require you to inform the other parent of where the child will be each night and provide a phone number where the child can be reached in the event of an emergency. Even if the order doesn't require this, it is a good practice and a courtesy to the other parent to do so.