Nice Bo! Any recommended National Parks in your vicinity? I have only been through a couple of time and stopped Phu Hin Rong Kla the once. I have always wanted to go back in the rainy season as the trees on the top would be beautiful with their moss coverings in the rain. Also had a weekend in Thung Salaeng Luang (I did not actually realize part of it was in Phitsanalouk) which I have always wanted to go back to, its just a bit far for a weekend trip from Bangkok. Beautiful park for camping and so many different habitats.
Sorry for the very late reply. Hadn't seen your post. I don't travel around too much around in Phitsanulok, so I don't have any recommendations. Phu Hin Rong Kla does look like a nice place. I will have to visit there some day.