The Sukhothai Historical Park is one of the most peaceful place to visit in Thailand. Its atmosphere is calm, quiet and full of good energies at the same time. The Ruins have all their own charm and brings you back in the history of the old kingdom. It's really easy to get around, by renting a bike for a day or two (around 30 baht), or even by walking around if the sunshine isn't too strong. It's definitely worth a visit while visiting Thailand. I'm sure you'll all enjoy your time there.