Well, it really depends on what month are you assigning your vacation month.
If you're planning to put your vacation month near Part 2 (December, November), then I advise you to take some time to study. However, if you were planning to take a vacation month anytime after January, then do whatever you want with your free month.
After interviews and part 2 (if you passed), there are not that many things to do, in terms of getting a residency. Again, every podiatry school works differently when scheduling their fourth year but ultimately, you should be fine.