This guide is the best route I've found for Ranger Hardcore
First off, you'll be at a disadvantage, you'll have lost most of your cool stuff and have to salvage what you can.
When Anna gets dragged off, hide behind the console (closest to the outside wall). Try to let the NPCs pick off most of the Cannibals at this stage as you'll struggle to stay alive. Keep an eye on the right hand wall and help Sam pick off the guys coming through there.
Once they're clear you go to a lift and are sent off on your own (assuming Someone died at the bridge). Loot as many corpaes as possible, hopefully the game will let you have some Molotovs.
This is the first real combat test of the game. You can not avoid combat here.
The first corridor is a pain in the bum, but once you get through it nothing should stop you from progressing up till the miniboss toward the end of the level.
as you open the door to the first corridor, the door gets stuck and you have to squeeze through. Craft as much ammo for yoyr guns as you can and steel balls as back up if you run out. Make sure to craft health as often as you can from your backpack also. THERE ARE NO CRAFTING STATIONS IN YAMANTAU.
Gun down the lunatic that charges you with a melee weapon and immediately hide behind the cover to your left. Wait til you hear someone shout "Meat", that's another melee weirdo, gun him down and throw molotovs at the gunners in the corridor. If done correctly, the support gunners should run straight in to the flames meaning you can now progress.
Keep going through till you come to a corridor where a pipe bursts killing everyone down the corridor and head in tot the vent on your right. (If it for whatever reason doesn't manually explode. Shoot the pipe high on the left and the game should also automatically save here). Once through the vent, look high on the right for a crawl space. This leads to a small walkway with two enemies at the end. Dispatch them and head to the room behind them for a lot of crafting goods in the locker.
Go through the tunnel and an melee enemy will charge. Dispatch him quickly and move on to the hardest part of the mission.
Crouchwalk round the corner to see enemies trying to kill Sam below. Aim at the gas cannister on the ground to the right of the floor on the floor. This will kill all four at once. Retreat and kill the melee guy that charges you and throw a molotov at the bridge killing a gunner. wait for a second melee enemy and once he's dead. Throw all but one of your molotovs down the corridor, this will take some effort in trial and error and may take a while to get right, but once done correctly, everyone should be dead.
Loot all the bodies for more molotovs, I had seven for the boss fight round the corner. Open the door and immediately hide to your right, kill the two additional enemies when the boss comes through the door.
Throw a molotov at him when hes near and two between yourself and him abd he should die. Kill the extra add and proceed through the level.
The next couple of corridors are challenging but you can sneak about and pick some of these guys off from the shadows. So use every hideyhole you can find.
The main obstacle I found was after rescuing Anna, the small lift is annoying, the AIs take the best hiding spots. So, hide next to Miller and take out the guys that spawn across the way. What you're looking for is to blow up levels with gas cannisters so aim for those.
Eventually you'll be back at the railcar. The easiest bit. Everyone hops on, let Damir kill everyone or join in on the fun (especially if you haven't picked up the kill 90 cannibals trophy already).
The trophy unlocks after the cutscene introducing you to the next area.