We are currently re-hashing our warehouse management software during the GP 2013 upgrade. In doing so I will be dismantling our terminal server on an interim trusted domain, and hopefully doing away with that domain all together therefore eliminating any security issues or concerns.
I chose to go with a MS Server 2012 R2 install with the Web Server Role and full IIS Features. At the moment I have the internal web site running and sessions are able to open anywhere on our network. I am ready for more testing with the GP test environment.