You have a time machine, but it has a drawback. You can't change anything. You can observe, you can photograph, photocopy and video, you can take things apart and put them back together, and if you're really sneaky, you can swap something for something that's effectively identical, but you can leave no evidence behind you've ever been there, you can't rewrite history, you can't even let yourself be seen or heard.
Where would you go and what would you do?
If I could do this, I'd try to be uber-sneaky. After her last battle, Boudecca was never found. No trace of her was ever seen again - amongst the living or the dead. Sneaking back to just after she vanishes from history and shifting her into the future wouldn't actually change history... would it?