Since I first traveled to Thailand I always liked Sukhothai and in the years that I am living here I did return many times. Of course Sukhothai is famous for being the first capital city of Siam (as Thailand was known until 1932). Nowadays Sukhothai consists of 2 parts, the new little city and 12 km west of it the ruins of the ancient city of Sukhothai "Sukhothai Historical Park", a World Heritage Site. The modern city of Sukhothai is still a upcountry relaxed small city with not much real big buildings or shopping-malls. And that is what I still like about it. Just to walk over the vegetable market or look people in the afternoon in the small public park. There are many nice guesthouses in the city to enjoy and experience real local Thai life. Just rent a bicycle or motorbike and explorer the city and its surroundings.
The old city can easily be reached by motorbike or public bus. Go in the afternoon or very early morning when the colors are much more beautiful. The historical park is actually very big and temple ruins are spread over a big distance, although the most beautiful ones are within a radius of 2km. Near the entrance of the park you can rent bicycles to visit the park or you can take a electric tram. It is really impressive to see how people centuries before did build all this without the modern tools we have now. If you are really interested in more historical parks like this, about 50km south of Sukhothai is Kemphang Phet Historical Park and about 30 km north is Sri Satchanalai Historical Park.