Mrigadayavan (Maruekhathaiyawan) Palace
Wat Khao Takiap
Train Station
Night Market - Seafood
Rajabhakti Park
Wat Huay Mongkol
Plearn Wan Shopping Village

mostly stuff Thais would want to do.

Helps to have a car, May tends to be rainy - beginning of the rainy season so you may get wet on a motorbike.