Altering the Nat. Wonder to Monarchy involves editing the CIV4BuildingInfos.xml
Specifically, in the entry BUILDING_NATIONAL_PARK, you want to change
Code:
<PrereqTech>TECH_BIOLOGY</PrereqTech>
to
Code:
<PrereqTech>TECH_MONARCHY</PrereqTech>
To make Forest Preserves available at Monarchy, in CIV4BuildInfos.xml for BUILD_FOREST_PRESERVE, again change PrereqTech.
To make the preserves themselves directly provide the +1 Specialist, there isn't a tag in CIV4ImprovementInfos.xml (where any such tag would need to be) to allow that. One alternative would be to make the National Park a regular building instead of a Nat. Wonder. If you were to do that, however, you should do a few things to really tone down the building - remove the Great Person points and stop it from removing all unhealthiness.
To do all that, you have 2 files to edit.
1)To make it a regular building, CIV4BuildingClassInfos :
Change the buildings iMaxPlayerInstances to -1 (-1 = no limit, 0 = disables building entirely, any other number is the maximum the player can build)
2)To make the changes I suggested for the now buildable everywhere version, in CIV4BuildingInfos :
Change GreatPeopleUnitClass to NONE
iGreatPeopleRateChange to 0
bNoUnhealthyPopulation to 0
Alternately, instead of changing National Park you could duplicate it (City Park perhaps). You would need to duplicate the entries in CIV4BuildingClassInfos, CIV4BuildingInfos, and CIV4GameText_Objects.txt changing the name in all three of the new entries to whatever you want it to be. And then, of course, make the changes above to the new entries.
If you do that, you
might want to set the Nat Wonder to require that you posses some number of City Parks before you can build it.
Something like :
Code:
<PrereqBuildingClasses>
<PrereqBuildingClass>
<BuildingClassType>BUILDINGCLASS_CITY_PARK</BuildingClassType>
<iNumBuildingNeeded>4</iNumBuildingNeeded>
</PrereqBuildingClass>
</PrereqBuildingClasses>
<BuildingClassNeededs>
<BuildingClassNeeded>
<BuildingClassType>BUILDINGCLASS_CITY_PARK</BuildingClassType>
<bNeededInCity>1</bNeededInCity>
</BuildingClassNeeded>
</BuildingClassNeededs>
