[How to go to the desktop when playing in full screen mode ?]

Windows key and escape usually works as it brings up the start menu

[Most rural lower league stadiums represented in FM (in England)?]

Glossop north end? Mossley?

[Promotion to the football league - conditions]

Regarding the ground issue you'd probably end up sharing with Oldham as they're the closest professional league club to Curzon

[*Official* Editor Feature Requests]

The ability to edit under 21 competition names ie English under 21 group (whatever). I edit the competition names (I prefer to do this rather than use someone else's work) and then it says for the under 21/18 competitions 'English under 21/18. I know there's a real name fix out there but as I said earlier I prefer to do my own work