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’ll visit past me and leave some letters that contain useful information. You know, don’t trust those people, avoid doing this mistake, know yourself etc. would be interesting to see how that timeline diverges from my own.
Actually. now that I’ve opened this door, might as well try influencing world history on a larger scale. How about I visit certain key moments where a dangerous person almost died, but survived to cause massive harm later down the line. Would be really interesting to see how history plays out after nudging Hitler a little bit closer than to that suitcase. History is just full of special moments like that.
I wouldn’t be a passive observer. I would actively change things to see what happens.
BTW, I believe in the many words interpretation of quantum physics, so all possibilities are equally real and they all exist simultaneously. No matter how hard you try to fix things or how badly you mess things up, that disaster branch was already there, always will be.
If you like fiction (and Stephen King for that matter), you should read 11 22 63. Main character goes back in time to change past events and things... sort of work out. It has a cool take on time travel and course of events in general, I was a big fan of reading it.
There is also a mediocre tv adaption of it as well if you're not into fiction, but I didn't finish it.
Some other books that handle time travel in fun ways and play with explicitly making changes to the past.