You most likely won't find "standing at the highest point in Thailand" on many bucket lists, though it's probably not unheard of. Should the idea pique your interest, however, take a jaunt over to Doi Inthanon National Park just southwest of Chiang Mai. By most accounts the area is, well, pretty tame (for instance, you reach the summit and its two adorning Chedis by car). Probe a little deeper, however, and you'll find some unique and rewarding excursions at your disposal.
There are multiple guided and unguided nature hikes available in Doi Inthanon, perhaps the coolest of which being those traversing the Mae Pan Waterfall loop and the trail to the beautiful limestone Brichinda Cave. These can usually be accomplished in no more than 3-4 hours, so those concerned about strenuous hiking can breathe easy. Camping in both tents and bungalows is permitted in several designated areas, offering excellent at-altitude vistas both day and night. The park is also fully facilitated, with information readily available at the main office, so getting in, out and around is a snap. Overall, it's an easy and enjoyable way to experience the top of Thai world.