OK - thanks to this list, I've made some progress,  but....

  1.  We've set up a VTI tunnel between the two PFSense boxes -- it works
  2. We have BGP enabled and when both ends are started up, the BGP routes are exchanged and then given to each side's OSPF
  3. Everything works, routing-wise -- things enter the kernel 
BUT....
  • After a while, it seems the receiving side loses the BGP routes -- if A publishes routes to B, B will lose the BGP routes.  I have to start both BGP processes again.   The processes were running before but I need to get the routes "re-published"
  • Static routes never go away - they are published all of the time
Clearly, I am setting up something wrong.  OSPF does a flood every 10 seconds.  How often does BGP do its "updates"