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You can take it early on, before Diamond City for a very hard challenge, the starting area will chew you up fast before traveling to Nuka World. You need Valentine, So a fairways past after reaching Diamon City, since you're heading horizontally across the map for that DLC, You'd be doing a whole lotta settlements and Side missions like Cabot Family. But honestly can be tackled at any time or any lvl, higher levels give more challenge so say when you Reach Diamond City.
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Very early on, eye bots spawn and events trigger. Plus you get a much better source of Electricity with this DLC I say this first since you need alot of materials and your settlements linked together reaching it is an almost must have to enjoy it fully. Huge Time sink, offers more building and is a fair ways past Diamond City, South of it.
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