How do you get to cranador in RuneScape

Crandor can only be accessed by boat after asking Ned to bring you to Crandor during the Dragon Slayer Quest. After the quest, use the underground tunnel which connects the Crandor and Karamja Dungeons. However, players must have found the secret door in the Crandor side of the dungeon during the Dragon Slayer Quest before they can use it on the Karamja side.