Just simply save the file as a new name even early2 works but it won't show that on the main campaign selector it will instead show somthing like this

viking
early
early
high
late

you can mod it to display a new name but I can't remenber how off hand.
Land bridges would be changed this way scroll till you see this

//========================================
//How do the regions link together?
//Region in question first, followed
//by its neighbours.
//Regions can have a maximum number of
//15 neighbours. Any more and Medieval
//will crash.
//========================================


SetNeighbours:: ID_SCOTLAND ID_NORTH_UMBRIA ID_NORTH_SEA ID_NORTH_ATLANTIC ID_IRISH_SEA
SetNeighbours:: ID_NORTH_UMBRIA ID_MERCIA ID_SCOTLAND ID_NORTH_SEA ID_IRISH_SEA
SetNeighbours:: ID_MERCIA ID_NORTH_UMBRIA ID_WALES ID_WESSEX ID_NORTH_SEA ID_ENGLISH_CHANNEL ID_IRISH_SEA
SetNeighbours:: ID_WALES ID_MERCIA ID_WESSEX ID_IRISH_SEA
SetNeighbours:: ID_WESSEX ID_MERCIA ID_WALES ID_FLANDERS ID_ENGLISH_CHANNEL ID_IRISH_SEA


Wessex has flanders as a neighbour which is across the english channel I'm assuming you can just remove ID_FLANDERS to do this as I have never done the landbridge one.