Hi DarkKnightComes, I've had a look at your quest, and here are my notes.

First and foremost, you need to follow our ID naming conventions for your objects, NPCs and scripts. They need to be prefixed TR_m7_ at the very least, and I would encourage you to add a unique identifier to the scripts, items and activators relating to your quests - for instance, TR_m7_HO_House_. Your NPCs also require the usual TR-specific variables - see T_ScNpc_Mw_Map7 for the relevant setup for your NPCs. At the very least, they need TR_Map set to 7, this is used to filter specific local dialogue. Also, to distinguish between NPCs and their scripts, add _sc at the end of the script IDs.

Also, I think the cost/reward balance of this quest is way out of whack. A house, a full set of Master quality alchemy equipment, and many valuable ingredients and potions, for essentially just 1000 gold. Here's what I'd suggest: rather than having the Bosmer be hostile, have him friendly - and trapped behind the treasure door after a falling-out with his business partner Goler - who locked him in the stash and ran off with most of the product. He thanks the player for freeing him, and sort of awkwardly offer the player to take whatever they want from their skooma storage, as he's leaving the business and going to be a legitimate alchemist from now on. Then have him AITravel to the middle of the room and serve as a merchant from there on out, keeping the house.

Now, the specifics - objects and scripts:

TR_Goler Ralvayn (NPC)

• Should have higher disposition to start with - I imagine he'd approach the player in a rather friendly manner, if trying to butter him up and swindle him.
• The shirt he is wearing a Morag Tong shirt, he will need a different one.
• Give him a 'thank you friend, you won't regret it' or something along those lines to say for the house for sale topic after the transaction has been completed.
• Level him up a bit, he's a pushover.

TR_GolerGone (script)

• add _sc at end to distinguish NPC and script
• Needs the aforementioned standard variables, see T_ScNpc_Mw_Map7
• As it stands, this script will continuously disable the NPC. Add in a check for GetDisabled to make sure this happens only once. The else return is also unnecessary.

TR_HouseForSaleKey (door script) 

• Needs a doOnce variable - only give the messagebox and journal update once.
• If Journal > 40, the door can no longer be activated and the player can never enter the house again.

TR_Door_Cornerclub, TR_DoorTrigger

• I get what you're trying to do here, but this is not the way to do it. There are two other entrances to the cornerclub, so the script that checks for the player's return simply cannot be tied to a door (you'd have to cover all three, and that's just ugly). Instead, move the relevant bits of this script to TR_GolerGone (script), and update the player's journal when they get within a certain distance of the (now disabled) NPC's position.

TR_Hundhalas

• Needs an NPC script and a higher level

TR_TreasureDoorUnlock

• You've got two Activates in here, which results in some odd behavior. Currently, once opened, the door cannot be closed again.

General scripting tip: if you're going to script a door to do something when activated, don't use more than one Acticate command, it has the potential to go wrong. Instead, do something like this, so that activation behavior stays consistent:

Dialogue:
In general, this could use a little bit of proofing. Your dialogue isn't bad, but there are some errors, and the tone could be a bit more Morrowind-y. But I liked that you didn't infodump the player and kept your entries concise. 

house for sale:

• So you're interested, huh? Excellent! It's a one-in-a-lifetime offer! once-in-a-lifetime opportunity!
• Add an entry for after the transaction is complete, so the topic doesn't just disappear.

connected to the house:

• This is a superfluous topic, just put what's here in the house for sale topic instead.

Greeting 5:

• Honestly, I'd not have a greeting relating to the quest for the other patrons in the bar. Just refer to the house for sale topic instead. Perhaps have patrons (filter for the cell name) refer the player to the barman instead, so that there's one convenient NPC to talk to for the player for this stage.

Journal TR_m7_HO_HouseForSale:

• "While being in one of the cornerclubs in Hlan Oek, I spoke with a man named Goler Ralvayn. He offered me a riverside manor for 1000 drakes. I accepted his offer and he gave me a key to said manor. I should head there now." --> Link to the main quest topic in the first journal entry: "While in one of the cornerclubs in Hlan Oek, I spoke with a Dunmer named Goler Ralvayn. He said he had a house for sale, and offered it to me for 1000 drakes. I accepted his offer and he gave me a key to the house."
• "I tried using the key on the door of the manor, but it didn't fit the lock. He must've given me the wrong key. I need to tell him about it." --> Who is he? Mention explicitly who you're talking about, just in case a player forgets, or returns to this quest after a period of doing different things. 
• "As I entered the cornerclub, I noticed that Goler is gone. Maybe I should ask someone in the cornerclub where he might be." --> Can be a bit more clear. "Goler Ralvayn is not in the cornerclub. Maybe I should ask the other patrons if they know anything about this house for sale."
• "A Dunmer named..."
• "I entered the house, but I'm also hearing someone else. Maybe it's one of Goler's people. I need to be careful." --> unnecessary, and I don't think vanilla ever lets the player 'hear' anything through journal. On the other hand, what you could do instead is to have the wood elf Say something. In fact, if you change the wood elf into a female High Elf, there are two voice lines that you could use for the 'trapped in the back room' situation I suggested above - "Someone! Help!" (vo\h\f\Fle_HF001.mp3) and "Over here! Help!" (vo\h\f\Fle_HF002.mp3). Play those, and *then* you have a good excuse to actually have the player hear something and a good incentive to explore further.
• "It worked! ..." such exclamations are best avoided, the journal is a pretty utilitarian piece of literature, with little need for flavor.

Journal TR_m7_OH_HouseForSale is marked for deletion but not quite deleted when I loaded this file, clean it out with TESAME.

A final, and very important point:
Testing, testing, testing! What are ways this quest might break? What happens if a player has already broken into the house before they talk to the NPC? What if they deny the offer, then break in, then accept it? What happens, as I already mentioned, when a player enters the cornerclub through a different entrance? What if you kill the quest giver? Does the quest stay active in the journal forever (it shouldnt!)? What if they've broken in, marked the location, and recall back into it, skipping the door the second time when the script on the door is what allows the quest to continue? (Addmittedly, that last one's a bit far-fetched)