A tutorial covering just about everything related to scenario building in Caesar IV may be found here.

My ambition is to create a Forum Novum scenario, with as close as an approximation to real Roman economic realities built in as possible…

postscript: A small program for checking your scenario for errors is available from this thread (scroll down). It checks for the following:

“When you load a scenario, it will check for these things:

– factories that are missing raw materials
– missing natural resources such as clay pits and iron mines
– resources that are available but can never be used
– resources that can be exported but are not available
– requests for unavailable goods
– scenario goals that cannot be achieved, including building and resource goals, and prosperity and culture rating goals

It will attempt to load the XML file and check some more things:
– missing keys for empire level cities, requests and goals
– wrong values for rating goals

In addition to this, it will show you:
– Maximum level that housing can attain (housing tab)
– The number of available foods and basic/luxury/exotic goods (housing tab)
– A list of all used resources, including their total import/export amounts and trade prices (resources tab)
– A list of trade cities with what they buy and sell, including the route type (water/land), cost to open, and their ID in the scenario (handy for writing the XML file) (trade routes tab)”

Handy, that!