Connection Timeout Expired without apparent network issue
This was eventually identified as a side-effect of VMWare LRO.  Disabling host-based LRO resolved the issue.  See 


Enable or Disable LRO on a VMXNET3 Adapter on a Windows Virtual Machine
Large Receive Offload
Poor network performance or high network latency on Windows virtual machines (2008925)
vmxnet3 adapter on windows server 2012 with MSSQL server bottleneck problem