[Imp]

Played a bit more & I can see for those that like their core to come out unharmed they may not like it as your core is really the least important units apart from your mortars, I have lost one.
Smoke is absolutely your freind here & the enginners are the guys that need protecting as they do all the work, clearing the beach & bunker busting.
Dont give up the arty hurts to start with as there seems to be a rocket battalion but of course they run out of ammo fast. It starts very hard but gets easier if you get your smoke in place.

SPOILER



Either I was very lucky with my arty or there are not many infantry units supporting the bunkers, snipers have been by far the biggest headache. Smoke & using the core for recon is letting the engineers get round the bunkers & deal with them in relative safety.
As you said if I had ignored easy red apart from a few perhaps to reveal the defences & landed everyone on the bottom 2 beaches a break out & circle behind the beach defences in force would most likely have been feasible. Or indeed everyone on easy red as it seems less well defended though my troops there are locked down, the arty is only small stuff but its made clearing the beach fortifications very problamatic. Still its all falling on them leaving the forces at the bottom of the map free to move unhindered.
Taking all the victory objectives is most likely not possible unless your mad enough to run into unknown territory on trucks but thats fine I anticipate breaking out of the bottom road & capturing those 3 victory hexes there by about the halfway point of the battle & then moving up to help easy red get off the beach. By then the sniper there will be out of ammo but boy has he had fun hes killed a lot of men.