note, this apparently doesn't work when you reach new haven, since enemies start spawing there. but before that, it's a perfectly viable way to get items/money.
while im here, i beat mothrakk...one mean son of a bitch, but if you run down the path you came where there's a car spawner thing, you basically have a roof to use as cover from his REALLY DAMAGING BOMBS HE SPAMS LIKE A MOTHERFUCKER WHICH KILL YOU VERY QUICKLY. pretty much wait for him to stop, run out of cover, hit him with whatever you got that can hit the flyers, then quickly run back. if you do this, and are careful, this guy is easy, but will take some time to down. i can't see fighting this guy the "standard" way (if there really is one) at the level you are supposed to do it. which from youtube, ive even seen people comment that even being level 27, they can't beat him. which this is a level 21 quest, i beat at level 23....and the mob itself (mothrakk) is level 25 for some reason.
*MODIFY*
this vidya here is for the chests in new haven
farm em for upgrades, money to buy shit, money to get the 1 million achievement, or if you are crazy, money to get your 9,999,999 "how much for the planet?" challenge. which can net you 20,000 exp(not worth the time it takes to farm that money in this place, but im sure there's better down the road).