I was 2.5 years old when my brother was born and I remember a lot about that night - being at home with my nan, what our curtains were like, how the room was laid out. What the hospital was like, the toy I was given, the fruit jellies that someone gave my mum. Everyone's always been surprised that I remember so much.
When I've done similar upgrades, I've often found it quicker to have the previous code available to me in another checked out repo rather than switch branches and have to deal with any possible uncommitted changes issues.
I went there last year on a tourist trip - walking around the exclusion zone and through the abandoned buildings was an amazing experience and I'd recommend it to anyone.