I have read that a AREDN node has the tunneling software built-in. How would one set up a arrangement where there are 3 nodes connected via DTD and a tunnel to another mesh?
The 3 nodes would be connected together via VLAN2 for DtD. As long as the nodes see each other on this VLAN, they will automatically connect with each other. The node running the tunnel software would be connected to "the internet" via VLAN1 (tagged), the WAN interface on the node setup. It is only necessary to run one tunnel server/client out of the three nodes.
You would then have 3 untagged subnets, one from each node, available for hosts and devices as usual.
Buy yourself a Netgear GS105E and configure it as described in https://www.arednmesh.org/content/gs105e-1-lan-3-node-1-wan
Connect your PC to port 2
The 3 nodes would be connected together via VLAN2 for DtD. As long as the nodes see each other on this VLAN, they will automatically connect with each other. The node running the tunnel software would be connected to "the internet" via VLAN1 (tagged), the WAN interface on the node setup. It is only necessary to run one tunnel server/client out of the three nodes.
You would then have 3 untagged subnets, one from each node, available for hosts and devices as usual.