if poss in hard or very hard cos the easier modes you don't really need a strategy, just a loaded gun!!
I *am* tactician myself, so even when I play medium, Il try to use more tactics and stretegy than run?gun
One way is to eguip yourself with DeLisle and Thompson, one with Enfield no4, one with Garand\Carbine\sniper\something like that, your choice and fourth with BAR (no Bren avaible). Also take flare gun + full flares with you, and also pliers\wire cutters.
When you start the mission, talk to that guy near you, so you have 5th man in this mission, armed with Enfield no4.
After that, sneak down to the road, use hold fire for your mate, then use DeLisle to take guards down carefully, if you do this correctly, no-one knows what happened. When the truck comes, keep hiding til it far away. If you killed the guards\enemies at the road carefully, the truck just passes the bodies like they wouldnt be there.
Then link up with rest of your squad at the house, and remember to give hold fire order.
Then sneak quite much to south to the fence, remember to keep yourself down to avoid detection. Then make a hole to the fence, move through it and keep moving at the south edge of the forest. You will find some random patroling soldiers but shoot them when you are close.
Then keep moving on, you soon find a campfire with 3-4 Germans, shoot them also with your DeLisle.If you do this once again correctly, no-one knows what happened - again.
Then clear the random guards at the forest, approach the depot from the eastern edge of the forest.
Then I suggest using tactical map to create a plan, that your rifleman moves to a good position, then when you give signal, it moves abit and crouches, this is good to watch your left flank.
Then with BAR, use same thing expect for prone, and so that he can see the gates. As you give signal, he opens fire. So in other words, I suggest using passive mode for all waypoints, and the final one after signal should be aggressive.
Then your Garand\Carbine\Whatever you have, depends on a weapon, but commonly you should make him move to the tower in the eastern part of depot from a signal.
Yourself, with your 5th guy, you should follow your Garand\Carbine soldier, Il explain later.
So now you have a plan, so I suggest making save if possible.
Then fire a flare over the base, and give signals to all your troops. As you shoot flare, half of the base rush to the gate and your BAR and Rifleman can take them out. Then follow your Garand\Carbine soldier, make 5th guy to have follow me and fire at will commands, and move to the fence, make a hole to it, and you and your 5th guy, clear the depot area, so no-one can defuse the bombs. After doing it, take the truck, drive close to your other soldiers, use "return" command and then "follow me", so they are in a truck. If possible, another save here.
After the save (if possible), rush through the checkpoint to the area where you eliminated those guys with DeLisle, quickly get out with your squad to safety, wait a moment, enjoy the show and rendezvou with the Resistance fighters.
I have tested this with normal and hard, and in both it worked fine. Only matter you may find that you have to time everything precisely or your whole operation may fall in few seconds.
As you play carnage mode, simply clear the whole base before escaping and when you rush through the checkpoint etc, get good positions so you can take them out from distance.