I'm currently looking at buying a new mesh  setup as my AmplifiHD no longer does what I need.  I like the look of the Eero, but I couldn't find a definitive answer to the one important question. 

TL;DR Can the Eero nodes be used wirelessly in a Router/Node1 -> Node2 -> Node3 setup, where Node3 is too far away to be able to communicate directly with the router/first node, and there's no way to run cables between them?

I have a log cabin next to my house and due to it's location I can't run any wires and can't use powerline, so I'm looking to extend the wifi out to there.  My router is located in a cupboard where the phone line comes in and I can have a node in my hallway which is not too far from the log cabin, although this in itself does not give a very strong signal in the log cabin.