If I had to choose one between’stop time’ or ‘travel to a time period’, I would prefer travelling a time period.
There are some moments in life that we will always remember. Those moments take up importance and make us smile or feel upset whenever we remember them. Life is weird; it can drag you from past to future or the opposite way, with the thoughts on your mind.
Sometimes you may feel that you are going to miss the moment that you are living now, and then when time moves forward, it really happens that way. I felt it once or twice in my whole life. It was a weird feeling because I was between ‘living the moment’ or ‘getting upset for the future’.
Its not all about the past; sometimes when you start to think about the future, you can’t stop yourself. You may wonder the results of something or the end of your life. And those thoughts may get you sick. So always thinking is not healthy for our mental health. I think it would be a smarter decision to choose to repeat the good moments and to correct things that we regret of the past or to remove our doubts about the future than to stop time. 
So travelling between time periods would be a great decision for me.