@simongeoghegan
As long as you take a backup of the .srm you needn't worry about anything.
The network share is the easiest and it only shares user data folders for retropie like: roms bios and configs.

The folder will be displayed like a windows directory in explorer, the local network doesn't need any configuration, it could be either through a router or directly connected through the ethernet.

@Capeman save states can be dangerous if there is a in game save. I've had it where the game thought I was using a different memory card and could no longer save to the main game because the memory card from the save state did not match the real one.
They are great if you're just trying to pass a part, but not as a save to come back to.

When you played them back in the days you played them on a normal TV, which has a lower resolution compared to the TV you're playing them on now.