How to access Raspberry Pi Cam without setting Router

I build a Video Streaming Server on Raspberry Pi to make personal CCTV for my parents. Then I think it can be a good service for other neighborhood.

Problem is my parents are not Programmer. They can't configure Router things. It is too difficult to Setting up outside External Access.

Is possible that setting up Raspberry Pi first time then don't need to do anything?

1. Configuring DDNS and Port Forwarding in Router. Most info about Video Streaming with Raspberry Pi recommend this way but Router is too difficult to them.

2. Ngrok. I also tried Ngrok. It still need to do something

3. Use SSH tunnel. I think it is a possible solution for my project. But I'm not sure SSH tunnel can bypass Home Router. Is it possible access raspberry Pi by SSH tunnel?

Please recommend other solution to me. Thanks for your help.