Hi Mooseman,
i usualy don't use scripts for that, but i guess there are a few guys out there making pretty good ones.
You can try this:
1- Place a trigger in the East camp with 200m (or more if you like, if it's open terrain), activated by West, detected by East. You can call it Camp Alarm or something like that.
2- Place several small groups (4 to 6 men), insted of few large ones, and make shure there are some machineguners in them.
3- Assign "Move" Waypoints to all groups, very close to their Leaders, and select "Safe" in the Behaviour tab. Synchronise this WPs with the alarm Trigger (select the synchronisation tab, and drag a line betwin the WPs and the Trigger, till they are connected with a blue line).
4- Next assign another waypoint to every group, and select "Hold" for some, and "Seek and Destroy" for the others you want to hunt you down. Experiment with "Combat" and "Aware" in the Behaviour tab, and "Engage at Will" in the Combat mode.
Now it would be nice to have a couple of 2 men patrols arround the Camp, so they wouldn't be caught with their pants down
5- Place somewhere a 2 men group, and assign some "Move" WPs arround the Camp, and then a "Cycle" WP next to the first one. Select "Safe" for Behaviour, and "Limited" for Speed. They will move slowly arround the Camp with their weapons in the back, but will react when engaged (if you give them the time).
You can create as many patrols as you want this way.
You can also use the alarm Trigger to bring reinforcements to the Camp, the same way you use it to make the AI react to the attack.
Now, the Camp will react from the moment the patrol spots you.
This is what you could call a basic alarm setup, there are more complex ones discribed in some of the excelent tutorials available.
Sorry for the long post, i hope this can help you.
EDIT: oops, 2 more replies while i was writting this! There you go, they're all good sugestions.