Bria Cloud and FreePBX

The Bria Cloud and FreePBX partnership seems interesting. My main concern is security. What would be the best way to lock down the FreePBX box while still allowing the Bria clients to access it? Currently, we used OpenVPN in a few edge cases to allow remote access but I don’t want to deploy that to general users - and have to support it or expect them to remember to VPN in.

How are other people locking this down and putting this into production?

Thanks in advance!