The treasure chests in Skuldoon weren't added until the Collector's Edition.
1 - Blacksmith's Shop
Inside the shop you'll meet the proprietor Turvang Hammer. If you're playing an early version of the game, then Turvang won't have much to sell, but in later versions he has a nice selection or arms and armor.
If you exhaust all dialogue options with Turvang, then you'll also learn that he once wielded a powerful hammer, and you'll get a dialogue option to buy it from him. However, Turvang will only "lend" the Thunderin' Hammer to characters who are demigoths (thralls, wylvans, urgoths, and zaurs). He'll claim everyone else is "too scrawny." If you get the hammer, then Turvang will tell you that you can add "zing" to it by taking it to the Altar of the Runes in the Forbidden Lands, but you'll only need to do this if you're playing version 1.4/1.5. In earlier versions, the hammer starts out with the altar's enchantment, and so you don't need to do anything to improve it.
Note: If Turvang isn't in his shop, then he's probably gotten himself stuck in or around the tavern to the south (#2).
2 - Bone o' the Boar
The Bone o' the Boar is the local tavern. Inside you can talk to the proprietor Ganspul Filto, but about all he'll do is offer to sell you dead goat ale (5 gold), happy jack brew (15 gold), and kick 'n da head stuff (25 gold). Theoretically, you can buy drinks to get Filto to tell you rumors, but we've only seen a few rumors from him, and they weren't that helpful.
3 - Ticket Office
Ticket Master Yugi will offer to sell you tickets to the arena (#4). Each ticket will allow you into the center of the arena, where you'll fight the creature indicated on the ticket. There are three kinds of tickets:
Note: In MMXII, minotaurs will drop a fourth weapon, the giant spiked club, but they'll also sometimes drop random gear, including mid-range magical gear.
4 - Arena
5 - Feros Duul
Duul sells nether spells and nether kataals. There are two campfires near Duul, allowing you to rest while you're in town. It's always a good idea to rest until 6 AM before going out to explore.
6 - Vartugg's Fortress
Directly east of the entrance you'll see a man named Mundruff standing behind a barred window. He is one of Vartugg's lieutenants, and he's also a shopkeeper and a guildmaster for the Guild of Mystery. To get in to see Vartugg, you'll have to show Mara's letter to Mundruff. Then he'll open a door in the southeastern corner of the room.
Vartugg will try to squeeze as much blood as humanly (or thrallingly, in his case) possible out of the situation. So he won't take Mara's letter at face value. He'll force you to vow that you'll secure an alliance with Lord Graemare himself, and that you'll forfeit your life to him should Valdane die before he is embraced by his father. Vartugg will also give you an empty vial and require that you fill it with Valdane's blood. But after all of that, Vartugg will tell you that Valdane can be found in the Naga Temple in the Sagathian Moors, and he'll give you permission to use the west gate of the town (Exit B).
Note: If you're playing the Collector's Edition, then you can push a loose tome in the southeastern corner of Vartugg's room. The tome will open a secret door leading to a pair of level 10 chests, plus some gold on a table. In MMXII, the chests are level 8.
After the Naga Temple
When you return to Vartugg after freeing Valdane and acquiring a vial of his blood, Vartugg will ask you if you were able to secure an alliance with Lord Graemare. There isn't any way to do this -- if you had traveled to Bolen Fields to visit Lord Graemare before freeing Valdane, you wouldn't have gotten a dialogue option to ask for it, and if you try going back to Bolen Fields now, Lord Graemare won't be there.
So you'll have to accept Vartugg's next quest: to travel to the Unholy Arc in the Vale of Ruin, to place the vial of Valdane's blood on the altar there, to meet with the messenger who arrives, and then to bargain with Voraatus to get back an item of Vartugg's.
Note: In early versions of Dungeon Lords, there are two quest log bugs here. The quest log won't update to show that you've rescued Valdane and acquired his blood, and you'll receive a new quest from Valkyra to go to the Tomb of Souls. Valkyra is the messenger who you will meet at the Unholy Arc, so ignore her quest until after you've spoken to her. Trying to go to the Tomb of Souls early won't work.
Another Note: In order to travel to the Vale of Ruin, you'll first have to talk to Staroxia in the Forbidden Lands, and then meet with Grymlok at his tower north of Lake Dire.
After the Tomb of Souls
If you haven't yet placed four relics in the Chamber of Spirits in Talendor, then you'll only hear that Vartugg is away on "urgent business." So if you haven't been to the Shadow Ruins or the Draedoth Temple yet, that's where you should go next.
After placing the four relics, Vartugg will return to his fortress, and, once you've returned his eye to him, he'll tell you how he doesn't get along very well with Barrowgrim. Then he'll tell you about the Witch Hag, who "nursed [Barrowgrim] yet suckles him still with her dark magic." Finally, he'll describe to you how he learned the code word "irynthabl" (an anagram of "labyrinth") to get into the Witch Hag's lair, located deep in the Black Swamp to the south, and he'll suggest that you might find Ellowyn there.
After the conversation, Vartugg will disappear, and you won't see him again.
7 - Maloke Brane (Collector's Edition)
On the upper floor of this hut you'll meet Maloke Brane. If you pay him 10,000 gold and then swear (and swear and swear) to him that you'll keep your word, he'll tell you how he acquired Valdane Graemare's equipment, and that among those possessions was a secret codex revealing the location of the Graemare treasure hoard. Unfortunately, Brane lost the codex to a bandit named Big Bad Mog, and he'll ask you to retrieve it for him.
You'll find Big Bad Mog, plus his good friends Gariss the Gutter and Warlock Kravenor, wandering around the Forbidden Lands. They seem to prefer the southern half of the lands, but they move around, so it might take a while to find them. A crystal of vision helps quite a bit for this sort of thing.
Once you do find Big Bad Mog, you'll have a tough fight on your hands. All three enemies are bosses, and they'd all be at least somewhat tough if taken alone. But with all three at once, you'll have to deal with a lot of stunning and bleeding wounds and magic damage. If you have a bunch of potions sitting around, then you might be able to just gut your way through the battle. But if you want to be a little more efficient, then you should lead the trio to Worglaw's village in the southwestern corner of the Forbidden Lands. The thralls there will help you out. They won't actually do a lot of damage to the bandits, but they'll distract them and absorb spells and damage, making things much easier for you. Just be careful not to attack Worglaw in the melee.
Once Big Bad Mog and his friends are dead, you'll find a bunch of good equipment: a blood reaper, a nether impaler, a totemic runemace, a sorcerer's hat, a kasa of speed and more. You'll also earn something like 500,000 experience just from the bandits' deaths.
Somewhere in the carnage you should also find Mog's treasure key. The key unlocks a safehouse in the Forbidden Lands (Forbidden Lands, #11). Inside the safehouse, you'll find a mimic and a pair of level 12 chests. Unless you're playing a rogue character, and probably even then, this is a good place to use a crystal of time to make opening the chests easier. Inside the chests, you'll find Graemare's codex and the helm of lords, plus some other armor and spells.
When you return the codex to Brane, you'll receive 25,000 experience and 5 points of honor.