While it is not needed to enter Despise, the dungeon isn't too complicated and has good loot.
Right from the start it is possible to descend the ladder at 1 to enter Heroes' Hole, an expert dungeon. Descending the ladder 2 gives access to the rest of Deceit. The ladder 3 leads to the other half of level one, while the ladder 4 leads to level three.
One level three, note the treasure locations on the map. Using a skiff to access ladder 5 in the middle of the lake enables access to the second half of level two, with lots of treasure.