You want a second view of your data where you only see traffic to a specific subdirectory. What is the best way to set this up?

Create a second Google Analytics account, and apply the new tracking code to the pages in the subdirectory
Create a duplicate view and add a filter: Select “Include only traffic to a subdirectory” from the Filter Type drop down, and specify the subdirectory
Create a new web property and add the new tracking code to the pages on the subdirectory