There are MANY ways you can approach this place, and there’s really no right answer, so I’ll just simply talk about key locations that you’ll want to check out!
The first location I’ll talk about in the main entrance to the school. It seems as though most of the fighting happens in TWO locations, here, and in the cafeteria dining area. If Ghouls spawned in, you’ll wake them up pretty quickly, but if Super Mutants spawned in, more than likely they’ll see you first. Either way, if you run up the stairs to your left to the upper area of the school, you’ll find a TON of enemies hiding in rooms. Most Legendary’s will be on that upper floor in various different classrooms, so many sure to search the whole area.
After you’ve cleared out this main area, you really have the option to head either to the cafeteria area, where the plastic is, or to the theater room, which SEEMS to typically spawn a ton of enemies all at once. The upper theater seating area is where most of the enemies spawn, so I’d start up there, and then make my way down and around to where the cafeteria starts.
The cafeteria room is WIDELY known across the community as “The Best Plastic Farming Location” and for very good reason. This room is FILLED to the brim with plastic cutlery, from plates, forks, knives, spoons, etc. Now remember, there are still physics in this game, so if you get into a fight in this room (which you are 90% of the time going to), DO NOT shoot at the tables, it makes everything fly everywhere, a real annoying time to clean up.
Like I mentioned before, this room typically spawns a bunch of enemies, both on the top floor AND bottom floor, so I’d recommend going in there, killing all the enemies off, and THEN farming the plastic. I’ve had legendary’s spawn in this room before on quite a number of occasions, so don’t be surprised if you catch a couple there.
After this room, we’ll be heading into what will be our final “loop” room, the kitchen.
The kitchen is YET ANOTHER fantastic plastic farming location, just simply check all the tables, counters, and food trolleys, you’ll find a TON of plastic all around this area.
The other thing you’ll want to check for is the Nuke-Cola vending machine around the corner, which obviously will have various drinks, and in THIS place, I’ve gotten quite lucky with the amount of Nuka-Quantum I’ve obtained from this one.
Make sure to farm the kitchen cooking room in the back, as it tends to yield a BUNCH of good resources and aid.
Lastly, this Kitchen will also be the spawn of a bunch more enemies, usually running down the stairs at the back of the room. Just remember, once again, plastic WILL fly, so try to fight these guys without explosive means, just to make farming the plastic afterwards a lot quicker.
On a good day at the Watoga High School Farm, I’ll get anywhere from 1-5 Legendary’s in this area, as it seems like Fallout 76 legendary’s are dependent on which enemy spawns inside. If ghouls, you have a much higher chance of legendary’s. If Super Mutants, you’ll get crowned enemies, but probably not as many legendary’s. If you’re hopping around grinding locations, you’ll no doubt get the various enemy spawns, including legendary’s.