Assuming that I have all the knowledge I do now and that I'm exiting from Vault 111 in place of Fallout 4's protagonist:
Upon leaving the vault the first thing I will do is make sure I can bleed. A large portion of Fallout 4's quest line that has been released seems to center around The Institute and synths. If I am a synth I will need to find some red liquid that I can use as "blood" or some other way to prove my humanity if necessary. If not, I need to focus on studying science in order to gain a firm enough grounding that I can pass myself off as a synth if necessary.
Now I start working behind the scenes, playing the factions against each other while getting rid of the extremists. After a while I start rumors about a third faction of cyborgs being created - that are extremely hostile, and have a clear advantage over both humans and synths. Next, I begin staging attacks on settlements in order to validate the rumors. The best case scenario would be humans and synths coming together to protect themselves against the threat, but if it doesn't happen organically I will need to make inroads with both groups in order to propose the union personally. After they seem to be willing to work together for the long term, I'll find somewhere with a warhead or high explosive and detonate in an uninhabited area and claim credit for neutralizing the threat.
Then I'll go back to the vault and see if I can replicate the necessary conditions to survive another 200 years so that I can see what becomes of everything.
Any other Vault:
Check radiation levels, find a skeleton to carry around with me, head for civilization.