Considering the Pailyn in Sukhothai?
A VT member wrote the following comment about visiting Sukhothai:
Historical Park part II by Mahieu
The park is situated in Old Sukhothai, about 12 km from the new part of town. Tuktuks are willing to drive you to the site for 100 Baht.
Inside the park, you can hire a bicycle to explore the park or you can take a ride along the ruins with a tramway. Of course, another option is exploring on foot.
It's better to go in the early morning, this way you benefit from an excellent sunlight for pictures.