Fallout 4, erm, 2293.
That's 16 years after Fallout 3, well enough time for some change to have happened.
Enough time for Outcasts and Talon Company to take over PP and have Lyons Brotherhood on the run.
Well enough time for Outcasts and Talon Company to form an alliance and expand their empire.
Or just enought time for Lyon's Brotherhood of Steel to unite with mayb other factions of D.C. to create a new country :thumbsup:
Well enough time for Harold's fruits to spread out over the world if TLW's decision to increase the rate of his growth was canon.
I hope that it's canon... I'd love to just here rumors of a place with clean water, trees, and grass.
So, 2293 should suit just fine.
Other than that:
Tactics II - 2215 (Barnaky ending)
Fallout: Arizona - 2286 (NCR wins in NV and they become far more militaristic and pushes through to Legion lands.)
Maybe Arizona could have some other factions besides the Legion and the NCR (Possibly a union of tribes, with a king)
Fallout: Core Wars - 2295 (Legion wins in Arizona, NCR is pushed back to Mojave Wasteland, core region is tired of NCR's inability to prosper and civil war breaks out between various towns which ends up with NCR becoming a far darker faction intent to re-conquer it's lands by "any means necessary".)
Down with Democracy! (just kidding)
That would be cool but eliminating the NCR completely would be bad, it would be reduced down to a small country made up of Shady Sands and one or two ther major towns.