yes, i can sympathize with your feeling about the heat. Petchabun must be one of the hottest places in thailand, rarely a day here april-september where we dont touch 40c. kao koo is def much cooler, its probably a good option for you, considering your feeling and where your wife is from. its close to lomsak, right? just be careful where you buy, and how you buy. many from around my area have been up there trying to buy land. its very popular now. we have also heard some reports of bad papers on the land, so be careful about that too. i can explain more in PM if you want.