Recommended level: 78+?
Required Skills: Max Burst Fire, Max Invisible Shot, Max Recoil Shot
Recommended Skills: Gaviota, Octopus
This map is a good alternative to Newties if you're not liking the monotony. I, for one, am not looking forward to doing 80 - 120 firing at newties, so this is a not-quite-as-good alternative as far as %/hr is concerned, but it's a lot more fun than sniping Newties.
First of all, always stay on the ship. You will never need to jump down to the ground to clear out the right - they'll move to the left themselves as you finish off the mobs on the ground floor. As far as how to clear off the mobs on the bottom, your bullets can hit the mobs on the ground just fine from the deck.
Now you might reach a point in which the bottom is all cleared out (like this). In that case, there's a simple two-part solution to your problem of attacking the top two decks if the spawn is too dense up top.
EDIT: I meant Invisible Shot in Part 2. I'm a dolt.
Careful, though, on Part 2. If the mobs spawn too quickly on the platform below the steps you may have to retreat back to the railing and start over. Or, hopefully by then the mobs will have respawned on the main deck and ground floor so you won't need to repeat this process. Furthermore in Part 2, the mobs on the platform at the bottom of the steps can hit you from that position. If nothing else, just blank shot to stun and use invisible shot to take them out.
This is a great map to choose if you went with Gaviota or Octopus instead of one of the elemental moves, like I did. In that case, do the following:
If the mobs become too thick on either the main deck or the ground (like this), you still have several options: (1) Aggro all of the mobs to the right, hop on the railing, and invisible shot them from above [this works with both main deck and floor mobs], or (2) If the problem is just with the ground mobs, you can hop along the main deck and use invisible shot. Make sure to keep Gaviota/Octopus spawned to keep them busy.