Borderlands – Returning to the Pirate’s Booty DLC

In playthrough 1, outside of the DLC, there's no such thing as scaling. Enemy levels are determined solely by the area they're in and your mission (certain missions effectively "level up" areas, notably Sanctuary and The Dust). You can easily check the level of an area by checking out the vending machines in the area, they sell items scaled to the level.

DLC in playthrough 1 scales to your level...ish. It maxes out at level 30. I played the DLC as a level 34 character and was disappointed to see everything was at level 30 in playthrough 1. Not sure if it has a minimum level it scales to.

Playthrough 2 works the same way until you beat the Final Boss; then everything in that playthrough scales to your level (except mission rewards for missions picked up before the final boss).

Playthrough 3 works the same was as Playthrough 2 after the final boss: Everything scales to your level, period. In team play, it will always be scaled to the highest level player's level. And you have to be at least level 50 to unlock it, so enemies are effectively level 50-61 at all times. Though if you take a mission before leveling up, the mission will still stay at that lower level, as always.

Basically the game works like a standard RPG without level scaling until you A) beat the game twice (because you should be maxed out anyway) or B) enter a DLC (because you can do that at any time so a preset level would be a really bad idea)

Most chests in one place are in Leviathan's Lair - 14 of them, countung the one in secret chamber. Leviathan's treasure room is accessible twice during the questline, plus there is a glitch to break into it later. There are hosts of instructions on Youtube, but I've found this one to be the easiest.

I'm about to start a second playthrough of Captain Scarlett, and will try to mark down all chests I find. If anyone has that information, let's work together!

Wurmwater

• 1 chest on the refinery supports, to be jumped to from a moving elevator.

Hayter's Folly

• 2 chests near vending machines in the middle of the map, in the water under a rock.
• 1 chest after Sandman, on the right.

The Rustyards

• 1 chest in the middle of first large shantytown ship you go through.
• 1 chest in top end of the second large shantytown ship, behind a shack.
• 1 chest on the last ship in the center of the map, right at the turret on the deck.
• 1 chest on the last ship in the center of the map, on the mast you climb for The Crow's Nest challenge.

Washburne Refinery

• 1 chest just before the Hyperius arena re-spawn point.
• 1 chest a little past the H3RL-E's lair.
• 1 chest in a secret room above the Arm (jump across the drop when returning from H3RL-E).

Magnys Lighthouse

• 1 chest on a wooden platform under a house near Maroonie's Secret Stash.
• 2 chests atop the lighthouse itself.

Leviathan's Lair

• 14 chests in the treasure room. See glitch.

Oasis

• 1 chest where you get the Horrid Hideaway challenge
• 1 chest at the building across the bridge in the middle of the map
• 1 chest in the southeastern most part of the map (Canyon Deserter Camp).