Hello Jeremy
I was facing a similar request to view which users are connected to my OpenVPN server. And I'll have to say that "/etc/openvpn/server.conf" doesn't exist in the current release of Turnkey's OpenVPN build.
It seems the original post author's method is the only one available, which is to look at the content in /var/log/openvpn/server.log file.
Cheers
Nick
Hello Jeremy