One of North Sikkim's greatest highlights is driving the 52km route between Lachung and Zero Point through the ever-changing scenic kaleidoscope of the Yumthang Valley. Though you'll no doubt hope for clear skies to see the mountains' full magnificence, swirling clouds can actually help emphasise their contours and let you focus on their natural botanical beauty. Ascending over 2000m, you'll pass through lush mixed forest, rhododendon groves, sturdy old pines draped with garlands of moss, and wild, tundra-like uplands above the tree line.
Around halfway, don't miss Yumthang Hot Springs: not for the tiny, unappealing bathing pool but for the approach across prayer-flag-draped suspension footbridges, with picture-postcard views of the towering valley wall. Beyond Yumthang's basic gaggle of shop and cafes, stop again to stroll Yumthang Meadow. Some tours end here; others continue another 30km up a seemingly endless series of hairpins to Zero Point (at a breathless 4825m).