After the Panda update rolled out, the latent risk in such a strategy could (typically would) vastly exceed the direct cost of the content, as poor pages on one part of a site could drag down the ranking of other pages on the site which targeted different keywords. Some sites have seen their search traffic fall over 90% with their ad revenues falling even faster. Demand Media went from being worth a couple billion to tens of millions of Dollars. ArticlesBase.com sold on Flippa for $80,000, but was making over $500,000 PER MONTH in profit before getting hit by Panda. Many other Panda-torched sites like Suite101 have simply went offline.
Use the Google Adwords Keyword Planner to find new and related keywords, but ignore the search volume data! The search volume data in the planner is really only useful for keywords that you’re actually spending money to advertise on. Otherwise, these volumes are not reliable. While not really helpful to decide which keyword is most used by your potential audience, Google Adwords Keyword Planner makes a useful tool in coming up with ideas for potential keywords!
Repeat this exercise for as many topic buckets as you have. And remember, if you're having trouble coming up with relevant search terms, you can always head on over to your employees on the front lines -- like Sales or Services -- and ask them what types of terms their prospects and customers use, or common questions they have. Those are often great starting points for keyword research.