Devan (VE7LSE), has a Winlink Gateway setup that connects over AREDN. More information from Groups.io.

1. Open a Telnet Post Office Session
2. Click on Add server
3. Click on Update AREDN MESH Node List
4. Click on Update MESH Nodes
5. Click OK on the Success Screen
6. Exit the Update AREDN MESH Node List
7. Select RMS RELAY WINLINK POST OFFICE - WL2K
8. Click Save

This will connect to VE7LSE's node:

1. Send message as Winlink Message
2. Post to Outbox
3. Open Telnet Post Office Session
4. Click Start

More info from Groups.io.