I've filled these plants up with dwellers trained as mentioned above. Vault door | Elevator | Triple wide Nuka cola plant | Elevator | Double wide Nuka cola plant I would advice against 'wasting' dwellers on the vault door, though. After that I don't think it matters which outfit they're wearing, but I'm unsure about that (haven't tested this). Best way to do this is getting a level 1 dweller, training it's endurance to 10, giving it the Heavy Wasteland Gear and sending it into the wasteland with 25 stimpacks and a few radaways(it shouldn't need these, but just to be sure). You get this by leveling dwellers up AFTER they've maxed out their endurance and if possible while wearing something that ups the Endurance stat. Other than that it's important to have as much health as possible. For the vault door (or vault defence in general) it's important to have weapons with high damage.