Can my husband have me charged with parental kidnapping if I want to take my kids on a 2 week vacation?

If your intention is to only take the kids on a vacation and return with nthem afterwards, then his kidnapping threats are ridiculous.  Absenting a court order precluding them from going, from what you have said there is no reason not to go on vacation.  Make sure he has an itinerary of your trip and is informed as to your whereabouts and has a way to contact the kids while you are gone.   

If you leave the state without intention to return then yes, he could probably claim you kidnapped the kids.  And if you had a separation agreement that specifically precluded it then yes.  And if you violated a court order in a divorce.  But taking them on vacation and showing return tickets probably a stretch.  But he can still make your life miserable trying.  Try and reason with him.  If it does not work then maybe re-think the vacation.  Maybe something local?  Or at least within the state?  Good luck.