There is a stand-alone installer for the TFS Object Model which is what you want: http://visualstudiogallery.msdn.microsoft.com/f30e5cc7-036e-449c-a541-d522299445aa
As far as the CAL question, it's a little trickier than you might think. Anybody that is interacting with TFS Work Items either directly or indirectly needs a CAL. This means if you have an automatic synch between TFS and some other system, anybody using that other system to view/edit data that ultimately synchs with TFS will need a TFS CAL.