Gentlemen (and Ladies), 
 
I can't beat Peace Walker right now...and need some help with the advance boss battles.  Would like to find 3 other buddies to play with, and hopefully let me beat this damn game.  Plus, I need help with the Monster Hunter Quests.  >.>  
 
Let me know if you're willing to hook up online, and help a duder out.
 
Thankee sai.

Like the end game battle? I would but I don't have a wired PS3. That's a dumb requirement of Ad-Hoc party. Unless there's a workaround for people who live in the 21st century and actually use wi-fi, then I'm down. 
  
Good luck, took me 40 minutes to solo it. Pretty crazy fight though. I'm literally exhausted from the stress. 

I still find wireless to have issues with staying connected.

should be ok to solo peace walker...
 
before you head out, make sure you 
-wear the BATTLE suit, or better, BATTLE W/H suit
for better protection, plus you can carry 3 guns with it.  BATTLE W/H is a random drop from A~SS rank outer ops
-bring up rocket launchers with faster reload speed like RPG7, LAW, M202 or M47.
DO NOT bring carl-gustav because it's weight would lower your running speed, making it hard to avoid peace walker's toxic beam and missiles
-a backup Machine gun
preferably rank5 MG3. if not, bring anyone with armor piercing bullets
or bring M16/M653/AK with grenade launcher, if you have the banada equipped and ultra good at arcing the grenades
because when peace walker's health is low, it'll turn on it's electromagnetic field, reflecting ALL rocket back to you.
if you so happened to only bring rockets to fight, you're fucked
-supply beacon
gun type if possible, since it hold 15 rounds, more than the 12 rounds of throw type
-in addition to rations, get the curry, soda and mate tea
you can't have too much healing items, plus the soda and tea can replenish your SP, preventing you from fainting after get hit by peace walker's toxic beam or powerslide.
 
while battling PW
-make sure you equip healing items all the time
also call in a supply drop when they starting to run low
-try aim for it's "knee"
somehow it deals more damage to PW than shooting the AI pod , plus it's easier to aim at
also try this when PW is starting a nuclear countdown when hiding behind the hangers
-be careful when you see PW jumped to sides of the docks 
it could be a preparation for the powerslide
it hurts F a lot but you can easily avoid it by staying close to either end of the dock.
-watch out if its head is glowing bright in red/orange
it's the electromagnetic field mentioned before
swap out your backup weapon and keep dealing damage, swap back to rockets when it stop glowing
 
manage your supply and healing items well
keep moving and keep punch it in the knees
you'll take it down eventually