Weight-reducing clothing
Ring of dueling/Amulet of glory
Slayer ring
Dramen or Lunar staff
Antipoison
Energy potion or Stamina potion
Rope
Some food if low level
Once inside the lair, head south-west into a room occupied by aggressive Kalphite Soldiers that can still poison you even with Protect from Melee activated. A stalagmite by the west wall directly across from the entrance can be used as a safespot to block them. After a full inventory, bank and repeat.
From either Castle Wars or Edgeville bank, the fastest way to reach the Kalphite Lair involves using the Slayer ring to teleport to the Fremennik Slayer Dungeon where a nearby fairy ring is located. Starting out at either bank, head to the fairy ring, use code , and run north-west to the lair. Without the Slayer ring, however, Edgeville and the Grand Exchange are still fairly close to a fairy ring.