Apologies to any i offend, but i am updating this thread with my notepad document that i use whenever i make a duplicate campaign,

STEP BY STEP
make a copy of the folders as detailed below,
then rename them as detailed below.

copy the following folder
Medieval\campmap\GameEnd\Vikings
and rename the copy replicant

copy the following folder
Medieval\campmap\Portraits\Vikings
and rename the copy replicant

copy the following folder
Medieval\campmap\Portraits\replicant\Vikings
and rename the copy replicant (*yes a subfolder of the one you made above*)

copy the following folder
Medieval\campmap\pieces\Vikings
and rename the copy replicant

copy the following folder
Medieval\campmap\pieces\Units\Christian\Shields\Vikings
and rename the copy replicant

copy the following folder
Medieval\campmap\pieces\Units\Muslim\Shields\Vikings
and rename the copy replicant

COPY the following folder
Medieval\Textures\campmap\vikings
and rename the copy replicant

copy the following files in Medieval\Loc\Eng
viking_faction_specific.txt and viking_region_specific.txt
rename the copies to
replicant_FACTION_SPECIFIC.TXT
and
replicant_REGION_SPECIFIC.TXT


copy the file viking_heroes.txt in Medieval\campmap\names
rename it to
replicant_HEROES.TXT

copy the file viking.txt in Medieval\campmap\startpos
rename it to
replicant.TXT

copy the viking unit and build prod file
rename them
replicant_BUILD_PROD.TXT
and
replicant_UNIT_PROD.TXT


OPEN the file replicant.TXT in Medieval\campmap\startpos

FIND THIS BIT
//========================================
//campaign name: can either be text or a
//label. Set predefined accordingly
//========================================
cn_predefined::true
cn_title::"Viking Period Title"
cn_short_title::"Viking Period Short Title"

//========================================
//campaign description: can either be text
//or a label. set predefined accordingly
//========================================
cd_predefined::true
cd_line::"Era_description_VIKING"

CHANGE IT TO
//========================================
//campaign name
//========================================
cn_predefined::false
cn_title::"replicant dupe campaign test"
cn_short_title::"replicant dupe"

//========================================
//campaign description: can either be text
//or a label. set predefined accordingly
//========================================
cd_predefined::false
cd_line::"replicant dupe campaign test"


FIND THIS BIT
// Do not specify the full path,
// only requires the name of the subdirectory off textures\campmap.

SetMapTexturesSubdir:: "vikings"

CHANGE IT TO
// Do not specify the full path,
// only requires the name of the subdirectory off textures\campmap.

SetMapTexturesSubdir:: "replicant"


FIND THIS BIT
//all Prodfiles must be stored in the Medieval root folder

Prodfiles:: UNITPROD "vikings_unit_prod.txt" BUILDINGPROD "vikings_build_prod.txt"

CHANGE IT TO
//all Prodfiles must be stored in the Medieval root folder

Prodfiles:: UNITPROD "replicant_unit_prod.txt" BUILDINGPROD "replicant_build_prod.txt"


FIND THIS BIT
//========================================
//Set the names and hero file for this startpos
//========================================

SetNameData:: "campmap\\names\\viking_heroes.txt"
CHANGE IT TO
//========================================
//Set the names and hero file for this startpos
//========================================

SetNameData:: "campmap\\names\\replicant_heroes.txt"


FIND THIS BIT
//========================================
//Set the region specific string file for this startpos
//========================================

RegionSpecificFile:: "viking_region_specific.txt"
CHANGE IT TO
//========================================
//Set the region specific string file for this startpos
//========================================

RegionSpecificFile:: "replicant_region_specific.txt"


FIND THIS BIT
//========================================
//Set the faction specific string file for this startpos
//========================================

FactionSpecificFile:: "viking_faction_specific.txt"

CHANGE IT TO
//========================================
//Set the faction specific string file for this startpos
//========================================

FactionSpecificFile:: "replicant_faction_specific.txt"


FIND THIS BIT
//========================================
//
// Override function for the portraits..
//
// When this is specified the game will
// ignore the factions culture when
// locating the portrait images and
// use this folder instead..
//
//========================================

PortraitsOverride:: FN_07 "vikings"

CHANGE IT TO
//========================================
//
// Override function for the portraits..
//
// When this is specified the game will
// ignore the factions culture when
// locating the portrait images and
// use this folder instead..
//
//========================================

PortraitsOverride:: FN_07 "replicant"


should now have seven folder named replicant
and six files named replicant

Start MTW,
choose replicant campaign

now you can mod away in those replicant files and folders to your hearts content,
if you change anything in names.txt or descriptions.txt make backups each time you make a change,
that way you can go back one step and try again.

B.