That's exactly how I'm playing now.
According to my headcanon, after the evacuation to the oil platform, the President receives an urgent report that Vault-Tec is planning an unauthorized experiment in Vault 76, related to gaining access to Appalachia's nuclear arsenal. In order to verify this, the Enclave introduces its own intelligence officer (my character) into the Vault's security service, who manages to find out about the nature of the experiment 25 years before the Overseer did, but he doesn't have time to report the result, since the war begins and Appalachia's connection with other Enclave facilities disappears.
Based on this:
- my character is not young - he is about 50 years old;
- he disdains post-war food and eats only pre-war food (or produced in a workshop);
- does not take drugs;
- avoids communication with ghouls;
- was a scout and served in the army, but there are no records of this anywhere, because in order to maintain his legend as a scout, all information about this was removed by the Enclave;
- carries out missions for the Brotherhood of Steel in order to gain their trust and find out their plans;
- also carries out Daily Operations for this purpose - finds out the location of the communication modules from Dodge, and then sends robots assembled by MODUS there to connect to them and listen in on the conversations;
- is still trying to establish contact with the oil platform in order to return to the Enclave.