Certainly. Open the dat folder in your WBTS folders - there are a number of txt files. Look around in those and see what you can figure out.
You can also take a look at what I wrote years ago for WaW (a similar game also from 2by3)
tm.asp?m=972044
My suggestion for your first attempt.
a) Open the cwscenario.txt file and make the following change:
//Scenario(7,regions61.txt,"Keith's test tutorial")
//ScenarioText(7,"Keith's test")
//ScenarioTutorial(7,cwtutorial01.txt)
is changed to
Scenario(7,regions61test.txt,"My test for 1861")
ScenarioText(7,"My test")
//ScenarioTutorial(7,cwtutorial01.txt)
b) Make a copy of the file regions61.txt and rename the copy regions61test.txt
c) Open the file regions61test.txt and make the following change:
REGION,2,Austin,PLAYER_C,Texas,TER_CLEAR
MOVECOST,2
POP,1
BPOP,1
FORT,0
CONNECT,1,3,4,352,353,
SIDE,6,6,6,4,4
ROAD,0,1,0,0
UNIT,RESOURCE,1
UNIT,MILITIA,1
changed to
REGION,2,Austin,PLAYER_C,Texas,TER_CLEAR
MOVECOST,2
POP,5
BPOP,1
FORT,1
CONNECT,1,3,4,352,353,
SIDE,6,6,6,4,4
ROAD,0,1,0,0
UNIT,RESOURCE,1
UNIT,MILITIA,10
Then start WBTS and open your newly modded scenario to take a look at Austin. Small change but you have to start somewhere. After that - experiment