If you're neutral or liked by the powder gangers, or if you're wearing a powder ganger uniform, then Dawes will demand 100 caps to let you into the facility.
Note: Just about all of the items in the facility will be "red," regardless of whether you're getting along with the powder gangers or fighting your way through them. However, if you noisily kill the powder gangers in one part of the facility (like in one of the cell blocks), then the powder gangers in the other parts won't notice. If your goal is to kill the powder gangers in the facility, then you'll have a much easier time if you blend in and kill them with sneak attacks (which won't alert anybody), than if you just go in with guns blazing. You'll just need to avoid bodyguards and named characters. If you're disliked, then wearing a powder gangers uniform will allow you to explore most of the area safely. Unlike some of the other powder ganger sites in the Mojave wasteland, the powder gangers here won't attack you if you're neutral or liked by the powder gangers faction.