Could you have averted the restoration if all of these factors happened?
Charles II goes to America in a successful attempt to salvage his power following the end of the civil war.
John Lambert and Charles Fleetwood manage to control the commonwealth by being more pro-parliament even if it is rather precarious.
George Monck on his way south is assassinated as he crosses the tweed (maybe by a disillusioned solider who doesn't want another war)
Charles II goes to America in a successful attempt to salvage his power following the end of the civil war.
John Lambert and Charles Fleetwood manage to control the commonwealth by being more pro-parliament even if it is rather precarious.
George Monck on his way south is assassinated as he crosses the tweed (maybe by a disillusioned solider who doesn't want another war)