Just rename your screenlayout presets like Default and Default Node so they are alphabetically next to each other, then Ctrl+Arrow is one keystoke to node editor and same back.

You can also change shortcut from user preferences > input > screen > set screen So its really one keystroke.

Just rename your screen layout presets like Default and Default Node so they are alphabetically next to each other, then CtrlArrow is one keystoke to node editor and same back.

You can also change the shortcuts from user preferences > input > screen > set screen 
So its really one keystroke.