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?
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.