We have successfully used Openvpn on RUT240, mounted inside machine with PLC, HMI and VFD, etc etc. machine being at customers site to establish connection with a laptop in our factory. There are few things to consider. If customer can set up their firewall and assign IP Address to the router, this is a bit simpler to connect to from anywhere. If customer can not do that the VPN in the router has to call out and to an IP (Static or if dynamic can use ddns server). It also becomes cumbersome if you have few routers trying to connect to your laptop at the same time. For this reason I tried to use VPN hub on RMS, but still having some issues with routing.