Copying AMFP files into CS folder, .msh + .anm?

[Romulator]

I figured the first time a map is loaded a checkpoint should be made, so a check goes in onstart, and each time the player enters a map the game should be saved, hence the autosave in onenter. What problems does putting autosave and checkpoints in onstart/enter cause?

You're better to do just the one Autosave in OnEnter();. OnEnter is called every time you enter the map, whereas OnStart(); is when you first enter the map. On your first enter of the map, you'd be creating two saves.