I have two fiber connection because i am transitioning to a new fiber provider.
Because of this i wanted to test if it was possible to use Roon from a “remote location” without Arc.
Why?, just for fun and because i can.
And yes, this actually works ands works well.
TLDR;
It works with two MikroTik routers using WireGuard and VXLAN.
No need for third part VPN providers and uses generally supported protocols.
You need to have very good networking skills to get it working.
It took a few hours, well a little more than a few, but hey, fun = fun.
Long version;
I use(d) MikroTik mAP Lite, MikroTik hEX S, Cisco Catalist C2960CG, C3560CG and a C2960CX.
Probably any vendor that supports WireGuard and VXLAN will work.
Mikrotik is my router to go because they are cheap, reliable and supports most, if not all,networking protocols.
I started testing with the mAP Lite remote and my hEX on the home network.
For a proof of concept setup i use a MikroTik hEX S on both the remote and home network to guarantee best possible testing (in my budget).
There are a lot of VPN protocols out there, but i choose WireGuard as i already use it for all my clients when not on my home network.
WireGuard is easy, safe, stable and fast and supported by most operating systems and router vendors.
After testing with some protocols for L2 connection, as we need an L2 connection to make Roon work, i found that EOIP causes issues but worked somehow and that VXLAN works.
What needs to be done, is to make a connection with WireGuard between the two routers (or more as that works to).
If the WireGuard connection is working, i use a VXLAN L2 tunnel over the WireGuard tunnel and connect it to the internal bridges on both the routers.
On the home network i use a VLAN for eg. Roon, so tagged packages into the bridge and untagged into the VXLAN tunnel. The remote side has no VLANs it is a Roon remote site only (with full internet access through the tunnels).
After this, we have an L2 connection between both the networks and not a routed L3 connection.
Make sure to set the MTU of the VXLAN to something like 2000, to avoid fragmenting.
For my clients on the remote location i use the DHCP server of the home network, but can also work with static addresses on the remote side.
It takes a minute or so after the tunnels is establish for all traffic to be stabelized.
All in all a fun project and have now further use of my effort to get my fiber working on my own router, without using the providers ugly big white box.
My mAP lite can now function as a router to connect to my home network and use it to listen to 100% Roon on a 100% not Roon Core location.
It can be used with wireless on both WAN and LAN and wired on the LAN or the WAN, nice.
Disclaimer:
You really really need networking knowledge and equipment that suppports enterprise protocol like VXLAN.
Because of the plethora of network connections and equipment it is not possible to guarantee anything, YMMV.
I know it works with my providers, with my networking equipment and topology.
I cannot provide support but am willing to give hints or tips when asked, or provide configuration hints for Mikrotik ROS.
Why am i not showing any screenshots? What is it you expect to see?, it looks the same remote and local 
If you know how i can proof this works, on the forum, please let me know, cables are cables that go into boxes, pictures do not proof a thing.
DISCLAIMER:
I have nothing to say about Sound Quality, it works great and sound great.
Even grouping with enpoints on both “locations” work without lag!
My opinion on SQ in the digital domain can be found on the forum.
Equipment used:
Tested on MikroTik mAP Lite and MikroTik hEX S with ROS 7.8 stable.
Home network with various Cisco Catalist switches and VLANs.
Remote connection is Telenor fiber and the home network connection Altibox.
Roon versions 2.0 (build 1259), DietPi RPi2, on the remote location …and some more on my home network.
Roon Clients are Mac book Pro intel and Apple silicon, iPhone 11, iPad Pro…
Thats all folks! Tinkering is fun!