When Steve returned the Tesseract to the 1970's, he lingered to watch her. His hands shook when he first saw her again, older, but with the same determined stride that could match his length for length. He had wandered through the compound until he found her marching across the base, and as easily as breathing he started following her.
He was not the same man who had gone into the ice.
The wrinkles around his eyes told that much; he kept his cap low over his face and was unashamed to keep his sunglasses on, if it meant he could watch her a little easier. He knew too much; he had seen and experienced too much of the future.
He had been to space, and here he was, going back to a year when calculators didn't exist yet.
Would she still love the older Steve Rogers that was coming to her?
Was this the right thing for her?
He followed her as long as he could, which took him outside of her office with the door closed. He knew it was time for him to go, but he passed her window to get one last glance at her.
She was holding his photo, thinking she was totally alone, unaware that he stopped in his tracks and knew, without the shadow of a doubt, that he was going home to his best girl.
It was Bucky's idea; send her a cryptic letter, saying the unnamed agent had intel regarding the Valkyrie and suggesting a meet up on Brooklyn Bridge that evening at 5. She couldn't turn it down. They picked a day in October 1945, just after the war, when they found a week of Peggy's life that was absolutely blank. It was like she took a few days off while she was in New York, and Bucky wiggled his eyebrows at Steve and made him blush bright red and chuckle. Steve arrived New York that morning, which gave him enough time to get a proper suit and take a few hours to adjust. He delivered the letter to her office in the New York SHIELD headquarters himself, disguised as a janitor. He left it on the very top of her desk and narrowly avoided a young Howard Stark.
He spent the next few hours sweating.
It started out with just his palms, which he expected, but the longer he was in New York- his New York- the more it felt like a dream. He looked at the skyline and could envision the Avengers tower in the future; he saw Times Square and loved it so much more without the glaring lights.
He put on a dress uniform and spent a few hours wandering around the city, opening an account at the bank, hiding in plain sight. No one expected Captain America, so no one saw him. A large briefcase he had picked up in the 70's held his shield and Mjolnir; he had the address of her New York apartment and wandered through the neighborhood, pleased that it was in Brooklyn and that she was plenty safe there.
If there hadn't been a brisk breeze, he would have sweated through his shirt.