Using "search and destroy" from the start is a sure way to have the army scoot all over the place.
With regard to the archers etc heading for the woods, the AI will try to route bowmen and medium foot through rough/difficult terrain if possible for protection against heavy foot and cavalry.
To be honest, the in built Editor AI commands simply aren't enough to make good AI on their own.
We didn't use them ourselves. All of the Historical Battles scenarios have scripted AI, and so do skirmishes.
There is a template scenario script called SCENARIOTEMPLATE.BSF in the main directory of the game. If you copy it into your user "campaign" folder, in the /SCENARIOS subdirectory (i.e. the place where your scenario .BAM file is), you can then rename it to match your scenario .BAM file.
So if your scenario is MYSCENARIO.BAM, rename SCENARIOTEMPLATE.BSF to MYSCENARIO.BSF. (Don't type in the .BSF, that will happen automatically)
You will find your user "campaign" folder in /Documents/My Games/PSCAMP/CAMPAIGNS.
Then you need to change line 36 from
to
and line 71 from
to
That will activate the Skirmish AI. See how the AI behaves then.
I suspect the archers etc. may still try to route through the woods though.