@Shawn Ackerman, excellent points!  

Huduser.gov creates a great market report that has excellent insight into market movements as a whole. 

Bottom line is that you have no credible evidence that your tenant is doing anything other than being a good grandmother.Explain to the neighbor that unless there is something illegal going on, you have no basis for breaking the lease and evicting them.

So far for us, BP has been an excellent source.

Using Excel, it's not too difficult.  

If you define you process well then even Excel or a project management tool such as MSProject can help.Paul, I think staying in your own backyard in the notes world is bad advice.

I purchase their raw data by zipcode(s) to analyze historical/competitive properties and massage it into the critical details I am looking for (need some basic excel skills).  

I use mail merge with excel data to create the letters.  

The tenants are not going to believe your words but might give credibility to test results from third parties.

Excellent comments.