Doing Kaplan from scratch is only going to pay dividends if you have a lot of time (6 months to 1 year)
If you are a rising 2nd year student, then this is perfect.
In the event you do have that much time, purchase another questionbank.
World is nice for honing your thought process, reasoning, and analytical skills, but it is hardly an exhaustive test of your Step 1 knowledge base.
(You will come to see that World is nothing more than a compilation of word games and logical traps... that being said, those aspects are what make World the Gold standard)