I farm the stockade chests for twink items often, and these are some things I've found out:
-There are always 2 chests in the instance, no more no less.
-There is one chest per wing, west and east.
-There is never a chest in the starting corridor.
-The chests are randomly locked or not locked.

You have to be at least level 15 before it will let you in The Stockade

[52,70] inside Stormwind City.

Remember to set dungeon difficulty to normal. ;)

Ok, A Horde's Guide to Stockades(or Greeting's from Stormwind)

After getting a lot of "How'd you do that" from Guildies and Puggerr's when they saw my achievment, i decided to write out how I got into the Stocks.

First head to The Jansen Stead in Westfall, from there head into the water and start swimming north keeping to the shoreline. After 10-20 mins of swimming you'll be near Stormwind Harbor; near the first dock is a gentle slope of grass. Head up on this and mount up, you'll be in Stormwind now from here head up the ramps into the city itself head around the Park's walkway, from there take the south bridge to the Mage Quarter, from there just run into the Stock's and get your achievment.

The looking for group function allows you to select the stockades up to level 29. At level 30 you can no longer select the stockades, which I find interesting (and lame) considering that it's listed as a dungeon for levels 24-32.

The obvious alternative way for a Hordie (lvl80 Tauren hunter, in this case) getting into the harbour is to take a boat. I used the one from Auberdine, since the mobs there are relatively low-level. There was a bit of a wait at the Kalimdor end, but I avoided any tedious swimming and rode through the city on https://vanillawowdb.com/?item=31835 Mr Non-Threatening here. Aspect of the Beast is also a good idea if you're a hunter.

Agreed that this is an excellent place to farm wool. I went in with zero and I came out with 78 after one run.

(edited for typo)

I really don't see how the guards in the entrance are so worried. If they can keep the criminals in the instance, they'll soon starve and then you can herd them into the cells again.

Says some thing about the stormwind guard if they cant stop a prison uprising in over 4 years. I mean in the time they've been trying to wipe out the prison we've killed illidan, knocked kil'jaeden back into the nether, defeated yogg'saron, and killed arthas.
By the time they clean out the stockades azeroth will be completely peaceful and thrall and varian will be able to frolic in the daisys.

In cataclysm, The Stockade will be seeing some pretty significant changes.

• The initial corridor will remain the "human" wing of the instance, with updated NPCs (they are Tno longer Defias gang members, but your run of the mill criminals). The final boss of this wing is a new character named http://static.mmo-champion.com/mmoc/images/news/2010/july/stockades_05.jpg Randolph Moloch and is the object of a quest where you need to switch him with his twin brother.
• The second corridor, down the stairs and too the right, is the "elemental" wing, and is obviously loaded with elementals (of the fire and slag variety). This wings final boss is the fire elemental http://static.mmo-champion.com/mmoc/images/news/2010/july/stockades_07.jpg Lord Overheat (blizz must be running out of elemental names) who will likely be the object of his own quest.
• The third corridor, down the stairs and to the left, is the "gnoll" wing, and if you thought https://vanillawowdb.com/?npc=448 Hogger would be the most appropriate boss for this wing, then you win a http://static.mmo-champion.com/mmoc/images/news/2010/july/stockades_10.jpg cookie . Elwynn Forest was merely a setback.

Since Patch 4.0.3 (The Shattering) The new bosses in The Stockade are:
Randolph Moloch
Lord Overheat
HOGGER

I guess Blizzard want to make a new level 25 boss with 20k hp? Interesting, considering he use to only have 666 and owned anyone that tried to attack him. xD.

for horde

yes you can enter, located in Stormwind City, which is in Elwynn Forest in southwest Eastern Kingdoms (little tower icon)..coordinates 50, 66

(not as heavly populated by players as Org is so not much to worry about)..2 lvl 85 guards at front door, i'm rogue so i just flew straight down from sky and stealthed,sapped 1 and walked right in... If not rogue just fly in door and go straight in, down small flight of stairs(should be able to get inside instance before you die), if not.. corpse run and walk in..

fast run at 85, about 5 mins.. no need to do left corridor(elemental side) if your just here for the wool cloth (elementals don't have wool)or to get dudgeon achievement.. I did however.. Also not a bad idea to wear low lvl tabard if not exalted with all cities yet i got 468 rep with Silvermoon at honored

used 45 bag slots

loot
gold/gray/worthless meat = 3gold, 51silver
59 wool cloth
12 linen cloth
1 silk cloth
6 greens
3 blues (to DE or Vend)
1 moss agate
1 elemental fire
1 elemental earth
1 pattern: Red woolen boots
not bad for 5 mins, all i needed was wool for an alt.. this is best place I've found