Need help with this project

Here is my current project I’m working on. I have a hundreds of sites that I need LAN access for troubleshooting through the 4G network. That way my techs can be anywhere in the world and can connect to these LAN’s to troubleshoot offline devices.

I also need some kind of setup in my field tech’s vehicles that will allow them to connect their devices via hardwired and wirelessly. So it sounds like I need two devices, one on the remote LAN side and one in the vehicle. This is not a common setup so that is why I am asking if this is a solution you can offer.

Thank you.

Isn’t something like Tailscale made exactly to cater for such requirement? I can imagine that it would work really well using a GL.iNet router on your remote LAN site and access all the clients connected to it from there.