Just use softether - free, simple, open source, fast and secure. Best of all it runs on almost any platform you could want to run it on (both server and client!)
You can even bounce off or azure to set up the tunnel when your vpn server is behind a natted firewall. It supports 16-channel connections to max out line throughput even over very long distances between server and client. It can support native windows clients, has openvpn shim for legacy client's on that side. I'm not doing it justice - there's so many features (all gui-configurable) that are supremely thought out.
Truly one of the best examples of free software I can think of.