Another possibility for addressing inter-site Roon use which I had thought about, and which may be more tenable is to use the ARC connection technology to create a Roon Proxy Server (a device that looks like a Roon Server on the local network - but actually works as a gateway to the actual Roon Server on the remote network. Such a device would use a ‘fast download’ to get queued tracks from the Roon server (not using RAAT) , buffer the stream(s) sufficiently to mitigate internet delivery latencies and then forward stream(s) to the relevant endpoint using RAAT/Airplay/Chromcast/whatever.
The user could then configure the Roon Server at their primary site and a Roon Proxy at a secondary site.
Remotes connecting to the Roon Server would only see the endpoints at the primary site.
Remotes connecting to the Roon Proxy would only see the endpoints at the secondary site.
Edit: Feature suggestion topic added at: Roon Server Proxy Device for access to Roon from a second site