Visiting Pa Hin Ngam National Park at Chaiyaphum
Visiting "Dok Krajiao" (also called "Siam Tulips") at Pa Hin Ngam National Park (Chaiyaphun). Although the "Dok Krajiao Ngam Festival" is from June to August, you can see at the moment in begin of August there are not much flowers. So personally I would advise to go end of June begin July. Entrance fee for the national park is 20 Thai baht for Thai (or residents of Thailand) and 100 Thai baht for foreigners. You can visit the flower-field by a slightly elevated walking path (500 meters walking), visit the cliff (50 meters walking) and visit the "Plain of Rocks" (800 meters walking).