I'll be in London for two weeks the second half of March 2020 and plan several day trips including Oxford, Cambridge, Canterbury, Windsor Castle, and Bath. I remember a few years ago visiting Dover Castle on a day trip and it was jammed with groups of school children. That made me think maybe Saturday and Sundays would be better. I've actually been to all those places, but mostly about 10 years or more ago and I know everything is more crowded now than it used to be. I tried to go to Windsor Castle in July a couple years ago and didn't pre-book and the lines were so long I just said forget it.
So, in March, what would be your strategy for visiting those places to avoid crowds?