I have planned to visit the Imperial Museum (the London one) on 21st April, which is the day of the London Marathon.
We will be travelling by train from New Malden to Waterloo.
I'm pretty sure we will not be impacted by road closures and general busyness as the route is north of the river at this stage, but I am not a Londoner so am not really sure.
I'm taking a child for a day out. If it was just me, I'd wing it and just do something else if I got stuck, but I want this day to run smoothly.