Blog Install While the Directory Site is Being Built

What is the best approach to installing a wordpress blog theme, while I’m building the main directory (using new Business Directory theme)? It will be at least a month or two before we finish customizing the directory. However, I’d like to start creating content for my website right away.

Given this scenario… should I install a 3rd party wordpress blog theme on my website? Also, should I install this at the root directory “website.com” or “website.com/blog” directory? I want to make sure that the blog’s URL structure and layout stays the same, after we roll out the Directory functionality in Business Directory theme. How should I go about doing this?

Thanks!