Rent a bike
And explore the ruins of old sukhothai walking will kill you. several rentals - price range: 10-50baht/day/bike.
Visit the park at sunrise
And admire the buddha figures in the orange glow of the morning sun.
Pay a visit to the ruins at Si Satchanalai
Historic park, 55 km from new sukhothai. few tourists, great sites, quiet. bike rental at entrance.
Walk around the fresh market (In new Sukhothai)
In the early morning and try the tastes of many kinds of local food sukhothai people like to have e. g. sticky rice with deep fried pork, sweet deep fried beef or spicy pork salad wraped with the banana leaf.
Rent a motorbike in new Sukhothai
And appreciate the local life style
Have "Sukhothai" Noodle!!
It is a must!