From: Arvada, CO
On the Invasion fronts, and I am no expert, I found that the sage advice of Pete Rizzo, former Police Commissioner and Mayor of Philadelphia in the early 70's appropo. "If the crook wants to fight, bring a knife, and if he has a knife, bring a gun." This is often summarized as "Don't bring a knife to a gun fight." For Allied invasions, several factors are involved. All are covered in the manual. First, scout the place out. Use recon, intel, whatever you have to determine who and what the defenders have. That tells you if it is a fist fight, a knife fight, or a gun fight. Second, you always bring a gun. Plan to overwhelm the enemy with a 3:1 superiority. That means whatever you bring should have AV at least 3:1 or greater than the defenders. A composite fighting group is likely what you need first, so the first wave needs to be the infantry or marines, the armor support (to reduce forts) and the combat engineers (Also to reduce forts). The support elements need to land after the island or base is secure. That would be the base force, seebees, and so on. Plant a defense battalion and plan to remove the division and armor right after taking the place, especially if it is a small island. Bring Air Units to nearby bases and fly them in once the base force and base is ready.
One thing that you need to work on is clearing the way with DMS ships to remove any mines. Then bombard the place with your bombardment force. Then land the attack units. Disaster awaits if you land the support units first, so don't even combine these units since you cannot control what off loads from a task force first. I damn near lost an entire invasion force when the D-Day offload turned out to be the support units and the infantry remained happily on the ships. So separate them into two task forces and make sure the attack force hits the target first. I use a liberal air cover from both land based and carrier air to support the invasion and turn away the enemy.
As for tracking the enemy using the Intel system, one can do that, but I find that recon is just as useful. I track the major movements of the enemy, but do not keep detailed records. I just do not have the time for that. I try to keep track of their intentions and what units they have moved or have in position in any particular area, and find that bombing them reveals a lot about them. It is important to note that if the position is heavily defended, ask yourself if you really need it. It is not too difficult to suppress major bases and just move on. Only take back what you must. You do not have unlimited resources either. If it is heavily defended, be prepared to commit several divisions to the effort of dislodging or destroying the enemy.
I am looking to invade Truk. I have 8 divisions tasked for this. Each division has an armor and combat engineer unit attached. Marine Defense battalions are also allocated, but only a couple will be needed. I am using Munda as my assault base since it can handle unlimited supplies and troops and is close enough to Truk to be useful. It is also surrounded by maximum bases at Lunga, Tulagi, Tassafaronga, and Shortlands. No chance of an enemy raid getting in there. I am presently moving the units to Munda, which will take another two months. Then the assault. I estimate that I will need close to 900 hulls for this. I have them.
I have benefitted in my campaign from the same early initiative that you demonstrated, eliminating most of what I call the "ant farm" before they grabbed too much territory. I have a battle of Midway victory in Jan 42, sinking three front line CVs off Noumea for the loss of Lexington. As a result I have been able to do most whatever I wanted too without much interference. Most of the enemy surface forces succumbed in the SOPAC as I marched right back up the islands to Buka. Hence, the enemy carrier force, which still is significant although two more CVs went down along the way, is still to be reckoned with, I can go whereever I want with the nine carriers and 5 CVLs that I have, which now have improved airframes aboard.
All of this is fine, but the real advice...always show up with a gun...and if they have one too, bring a bigger gun and more bullets.