Another spot just outside the BNK-3R zone is if you zone there you can kill the BA Constructor over and over, pretty easy from that platform where the red chest is(plus you can farm the red chest and the 2 lockers). I think that constructor gives 10k xp though that could have just been because of the quest for going to BNK-3R being active. The Contsructor cant hit you as long as you stay hugged to the fence and you can shoot through the gap.
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While you already mentioned the Arid Badlands for chest farming, I think its also one of the best for quick power leveling. maybe because it is a late game area, but there is a ton of XP to earn and if you want those one or two levels before facing the warrior, this area can get you there in no time.
With at least 4-8 rabid skags that spawn (at about 5000 xp) to bonehead 2.0 (also about 5000) and the multiple skags and loaders, its a lot of xp. And if you have the weapons to take out Saturn easily you can add in another 20,000! and you've already mentioned the chests that make this area perfect.
the quickest way ive found to run it is-
1. take skags out in front of main entrance. usually a rabid or two spawn here. 2. jump off ledge and kill the 3-4 skags in the slag pool. 3. take the left towards T.K. Bahas place, if your strong enough you can get the skags to follow you up to the skags in front of Bahas house and take out the two groups at once. this may be difficult, since you may end up fighting 2-4 rabids at once. ive had 6 spawn! If too much, just kill separately. 4. Continue past bahas place to the skag spawn right there in front of the rock wall. 5. Turn around and enter the bandit camp, there will about 6 loaders in here. 6. exit the bandit camp near the left, there is a skag spawn to the left of that bandit camp entrance. 1-2 rabids can spawn here too. 7. Enter camp and kill Bonehead 2.0 and loaders 8. keep going through killing loaders making your way towards saturns spawn. 9A. Jump on building and grab chest, you can also shoot the switch for the chest in zeds from here. 9B. (optional) Kill Saturn 10. Collect Zeds Chest, kill few remaining loaders then turn left past zeds house for the last Skag spawn.
Once you get your individual technique down this run can take 5-6 minutes and net you about 2 and a half to 3 bars of experience. completely ranking up takes around 5-6 runs.
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