Does anyone have information on simplifying / configuring TFS for secure environments?
TFS uses Windows authentication, so it is as secure as your network. I suggest that you also check resources for enhanced network security.
Team Foundation Server Security Concepts
Team Foundation Server Security Architecture
Team Foundation Server Security for Users and Groups
Team Foundation Server Security Using HTTPS and Secure Sockets Layer (SSL)
Troubleshoot Foundation Foundation server permissions and security issues
If you have not yet viewed it, TFS comes with a command line security tool, TFSSecurity.exe