Wondering whether anyone has been playing around with http://zerotier.com?
ZeroTier delivers the capabilities of VPNs, SDN, and SD-WAN with a single system. Manage all your connected resources across both local and wide area networks as if the whole world is a single data center.
I have found it very easy to setup encrypted lans spanning my laptop, my home laptop, a local vm and remote vms. https://github.com/zerotier/libzt in particular looks very interesting for embedded. Imagine a globally accessible lan spanning your devices, datacenters, networks and applications.