re West Yellowstone to Colter Bay.... 2 to 3 hours depending on traffic and not counting sight seeing stops (like Old Faithful, etc)
older kids are tough because they are addicted to their I phones and won't be happy with limited service in the parks. If they like action, try a horseback ride up in Yellowstone and a white water river ride in Jackson. Or the ski lift in Teton Resort. Also, you can get a chuck wagon hay ride/dinner deal in Jackson..not sure about Yellowstone. And Jackson has a rodeo and a shootout on the Square.