Summiteer

Base camp: ropes to get back down, cairns to find your way, a tent to sleep in, and wind that won't let you pearl past a climb.

• Trail cairns: mark your way up, find it again on the way down. A small stack of stones that gives off a little light and a wisp of snow; in a whiteout it chimes softly every few seconds, so you can follow the sound when you can't see. 3 cobblestone (any stone) and a torch make 2.
• The base camp tent: a bed you can carry. Right-click it to set your respawn, sleep in it at night, and sneak-right-click to pack it up and take it with you. In every wool colour: 3 wool and 3 sticks. Beds are left as they are.
• The wind takes your ender pearls. Above the treeline a thrown pearl drifts downwind: a few blocks off target up high, more on a summit and in a storm. Under a roof, or below the treeline, pearls fly straight. No more pearling past a climb.
• Rope and anchors: your way back down. Place an anchor at a cliff edge, facing the drop, and right-click it with rope: the rope unrolls straight down to the ground (up to 32 blocks). Climb it like a ladder, faster in climbing gloves (step up onto it even from snow or tall grass at the bottom); sneak-right-click the anchor to reel it all back in. Works on any cliff, ravine or build. Rope: 3 string make 4. Anchor: an iron ingot, a stick and a stone block.
• Peaks always count as high ground. Frozen, jagged and stony peaks (and other mods' peaks) get the mountain weather at any height, so a low range of peaks that tops out under the treeline is no longer calm, and the ice axe grips their rock. Meadows, groves and slopes still need to be above the treeline.