Once he's on the base, will they tell him where to find the character he's searching for? If not, can he wander the base looking for the other character? Because of the secret nature of the Stargate Program, I think Sheppard is technically "assigned" to Peterson Air Force Base (his brother mentions trying to send letters to him there in cannon) and this is the base he will be trying to visit, if that helps him out any.
Someone gave me a lot of great information, so now my main questions are:
How can he find out what building this person works in? Where would he go and who would he ask to find that out? Would they just tell him this information freely or is he going to have to explain his purpose for being there?