When President Lincoln didn’t sleep well he sometimes wandered to his office and worked, with the whole East Wing unoccupied except for himself and the messenger sleeping in the anteroom.

When the Lincolns first occupied the Executive Mansion, ingress and egress was entirely unobstructed. All the doors on the Pennsylvania Avenue side of the mansion were open all through the day and very late into the night.

Source: White House Community by Ronald D. Reitveld, Journal of the Abraham Lincoln Association