Finished the scenario.
Final results were 3157 vs 369 (in favor of the USMC) with all VH's in USMC hands.
I did replay the first 3 turns once (due to crashes) so it wasn't completely a 'virgin run'.
My advice on how to deal with this one is completely opposite to Pyros' advice above!
1 - don't leave your foxholes, they're your best asset.
The only exceptions are the FO and possibly the HQ if the enemy get's to close. Both units are too valuable to waste away in firefights.
Foxholes will prevent almost all damage from enemy artillery, reduce the suppression caused by it and improve the rallying of units in it. It'll give some protection against direct fire and make your units harder to spot. Use them!
2 - use your air and artillery against enemy ground forces close to your line.
Don't waste your few assets against enemy artillery positions. It's futile, there are to many of them and the best you can hope for is a temporary suppression and even that isn't that likely. By targetting the infantry (and armor) you can inflict serious casualties and most importantly, suppression. This suppression will result in the enemy forces arriving at your foxholes piecemeal instead of in swarms (see next point).
3 - keep out of sight from 'stand off' units by employing smoke.
Smoke can be a defenders best friend. It'll keep enemy units that are at distance from firing at you and suppressing you to let their friends come close and finish you off. Your unsupressed units will slaughter the enemy once it comes next to your unit (which should still be in its foxholes). By using air, artillery and area fire from units further back you should pin as many units as possible to prevent swarming attacks on your positions (once your unit runs out of optny shots it'll be a sitting duck).
Besides smoke from arty and inf units you can also use smoke from destroyed vehicles (so try to destroy the tanks when they're right in front of you instead of from a distance), smoke from fires (use the napalm to create a flaming smoke screen in front of your line and catch some enemy infantry in it), and smoke from firing (are fire from a hex will cause smoke in that hex to appear after a number of volleys and firing into a hex will also cause some smoke there after a number of volleys in that hex).
Enemy units next to you that retreat due to losses you inflicted will often pop smoke when doing so which off course helps you more then them!
4 - keep your reinforcements back (second hill line and village) and don't expose them to enemy arty. If possible get them in foxholes with other units for added protection. Their job is to take care of enemy units slipping through which will happen at the northern and southern edges of your line. Keep your tanks between the two lines until a few turns from the end, you'll need them to retake some flags.
Put a tank asap near the crossroad north of the village (the VH southwest of it is a good hex).
5 - you will lose your forward line of units (most of them anyway). Can't be helped, point is that the enemy should suffer huge losses in overcoming them and be unable to get over on the top in any force. Your survivors should be able to hold on and mop up the remains in last few turns, retaking all VH's.
6 - use your planes to recon behind the smoke.
Have them fly in or out paralel to your line (a few hexes in front of it). They should spot (most) of the units they overfly and give you a good indication where to aim your artillery and area fire. It'll also make them strafe enemy units close to your troops. Don't worry, I didn't have a single friendly fire case!
Some obsevations on the scenario:
On turn 12 I got 1 Pershing as reinforcements. I played half of the turn and then saved the game to continue later. When opening the half played turn again, it started by giving me the second Pershing slotted for that turn as reinforcements! Is that supposed to happen that way? Saving and restarting can be a trick then to get reinforcements as quickly as possible.
Of all the aircraft armed with bombs and napalm (weapons with a '0' range) only 1 dropped part of the ordnance in the hex it attacked. All the others started dropping it in the hex after it. So the plane flies in, strafes a hex with an enemy unit in it, then drops it load in the empty hex following it (and yes, it was empty). In other words, the heavy loads were pretty much useless. Hence my advice not to waste them on artillery positions and use the napalm as a 'flame screen' for your troops.
Remco