Battle for Middle Earth - Good Campaign - Helm's Deep

Battle for Middle Earth - Good Campaign Map - Helm's Deep (+30 Command, +2 Power)
This is a hint/walkthrough post for Battle for Middle Earth. You can find an index of all our Battle for Middle Earth posts here.

There are piles of treasure in a nook near the main gate, and in the far west corner of the city. When the peasants come, grab their treasure and hotkey them. Move them behind the main gate because there's a battering ram coming and they can repair the gate.
Initially, build farms everywhere. Do NOT erase any buildings you are given because they will not reveal any build sites. Save two build sites for a Stable and Armory; the rest can be farms. Later, you can destroy some farms and swap them with Wells, especially right behind the gate because you can then send defenders back there a shorter distance than running them all the way west.
You will probably be too busy defending Helm's Deep to tend to your build queues, so just recruit some horsemen for now and upgrade everyone with whatever you can. Fire arrows are very useful, but not truly essential -- focus on getting a good force of Rohirrim first.

While Isengard is on its way, put all archers and horse archers together with Aragorn (who can give an XP bonus) and have Legolas use his Train Archer ability on them as many times as you can. If you have the Elven Forest power, use it to line the outside of your walls throughout the mission.

This is an easy mission if you don't panic and don't let anyone outside. Be careful of your heroes, especially Gimli, because they seem to want to go outside if you have a Postern Door in the wall. Do NOT build a Postern Door in the west wall because that can really confuse pathing and units can end up outside, especially if you target a ladder -- the pathing tries to take a unit outside to attack it from the ground, instead of attacking it from the wall, which it can. Don't target the ladder -- Instead, use "A" to give the attack order, and right-click to give a move order so that a unit attacks everything along its move path. Set the move-to point very near the ladder.
During the siege, the elves and heroes should be able to hold their own with little micromangement on your part. Have your Rohirrim run along the walls to sweep them clear whenever the enemy comes. Don't run Aragorn around -- instead put him in the midst of archers to take advantage of his Leadership. This means fewer archers can defend a wider stretch of wall -- Aragorn's Leadership power has a really wide radius.
If Isengard manages to bomb your wall, don't panic. You have Rohirrim to sweep them aside and help your archers plug the holes.
Once the ballistae start coming, build a Postern Door to send out your Rohirrim to quickly take them out. Retreat your forces from the wall if you can and send them to a well.

If you haven't got Fire Arrows yet, send out Yeoman Archers to get killed and free up Command Points to build more until you get a level 2 Archery Range. Send out the Yeoman Archers to get killed so you can swap them for Elves. Do the same with the Peasants once they've repaired anything you need repaired in Helm's Deep.

For the final assault on the camp, leave the Elves to watch the walls and send out your Rohirrim. Advance slowly with Rohirrim Archers -- fire arrows can take down buildings very quickly. If anything advances on your Rohirrim Archers, take them out with your Rohirrim Warriors. Otherwise, let the Archers do the work.