VPN’s are great to use with ROS. I use tinc because its easy to setup, OpenVPN seems to be the more popular choice. One thing to note is that the VPN will increase video latency. I’m currently trying to figure a way around that using something like webRTC.
I’ve used RMS before. Its okay, but it could certainly be more configurable. I stopped using it and write my own web stack based on ROS Java
Last thing I’ll throw out there is a startup called ROCOS. They are creating a system for cloud connected robots that looks really legit. They are still creating it but once its done you will pay a certain amount per robot per month for this stuff to just work.