I have to agree with Kapitan - in the vanilla HC mode, food and water were too plentiful and you only needed to sleep something like once per week.
I seem to recall installing a mod within the first week of release that drastically increased the rates for FOD/SLP/H20, increased all merchant prices by 5x and cut resell prices in half. That was a gamechanger and the only mod I needed to give hardcore mode some teeth until Arwen released her Realism Tweaks.
Talk about challenging!
With Arwen's Tweaks I have to approach every encounter very carefully, sometimes using frag mines or explosives in strategic locations.
if you get hit, you develop a wound that you can't heal during combat.
if you bleed out you start losing too much blood and you have to use bandages or a belt as a tourniquet to to slow down the bleeding or inject a stimpak into the wound (reduces your STR and can only be done outside combat)
If you lose too much blood your carry weight goes down by 15 pounds. it can be treated by a blood transfusion
If your wound infection level gets too high you start continuously losing health unless you treat it with antibiotics.
If your left or right arm is crippled, you can't use rifles or 2-handed melee weapons.
To treat fractured limbs you have to apply a medical brace for a period of time until it heals. For fractured skull or ribs, you have to inject morphine into the fracture. You can only use a doctor's bag if your medicine skill is high enough (I think 50).
Eating food and drinking liquids does not provide HP.
if you don't cook your food it increases your Bacteria Level quickly and if it goes over 5.0, you get Food Poisoning.
The total carry weight is massively reduced (walking around with some injuries, I can only carry about 70-80 lbs as a 2nd level character with 6 STR). Skill magazines all weigh 1.0 lb and the skill boost is cut in half.
So - I'm interested in checking out Josh's mod but it seems like I will probably need to start a new playthrough and carefully review all the modules in Arwen's Tweaks to see what might conflict etc.
EDIT: Incidentally, Arwen mentioned she is working on her Skyrim Tweaks mod - can't wait to see what that will entail.