Assume you have all the luxuries of a modern life in your Tardis (toilet, hot showers, TV, books, game console, ...) which doubles as a mini self-sufficient apartment with it's own energy stores and generation.
Where in history would you go if comfort wasn't an issue?
I've given this a lot of thought but I'd love to meet oppressed historical figures. I'd love to see people autonomously standing up for themselves like at Stonewall and The Battle of Cable Street. I assume that they are both more brutal than anything I can imagine but it blows my mind to realize how many people came together.
I'd love to see the parts of town where the post-WW2 "slum clearings" took place. Gentrification is having a real impact here at the moment and its a shame. We recently lost a shabby 80s community centre and the building that replaced it never got the community back. Honestly, I just want to walk around here before the cars arrived.
A stranger thing that I would want to see is the old wood-paneled stock on the Metropolitan line of the London Underground in service at its peak. I generally would just want to explore transport systems as a whole. Getting to ride a 1910s tram on the street would probably feel surreal.