The Burrows is QUITE the extensive place to get lost in. Surprisingly, over time, you’ll start to understand the similar looking corridors and know how to quickly run through, kill everything, farm the legendary’s, and then get out.
By starting at either sewer entrance, you’ll immediately be greeted by hordes of ghouls just waiting to be farmed up, and as you work your way through, making more and more noise, more ghouls will be attracted. The BEST way to approach this place, as no great map has been charted out for this location yet, is to simply make a loop around. Hit every room as you can along the way, chart the place for yourself, and begin to understand how this big loop connects from one side to the next. There are MULTIPLE rooms absolutely filled to the brim with ghouls, so no room should go unchecked.