theoretical physic, Engineering (You don't need advanced tools to achieve the optimization and some of the inventions we use in our daily life), medicine, farming....I mean there are many domains where you can have an advantage over the past but woudn't be boring to live in the past especially in an era with no electricity or computers and stuff, of course you'll get used to it quickly but still the thought that you have to change all your hobbies and life style to adapt to the periode is a real hasle isn't it