Find an ice wizard, or create your own, who can craft the Blizzard treasure cards. Occasionally, you'll find one in the Bazaar, but not that often anymore. I believe the Ornamental Stepstone is available from Wul'yahm in Krok, if he doesn't have it, you may have already bought it.
Got the planks, the four wooden water towers, the two water fountains, most of the step stones, half of the grassy mounds, and one of the four carved stone tower or whatever it is. Got the Blizzards too. Funny thing is, right after I bought the recipe, I went to the Bazaar and could find a bunch of Blizzard, not enough, but some. Now it is EMPTY! But I thought the recipe was added in June, not September, so you would think the initial rush is over.
If you are desperate, you can farm Krokotopia bosses for Blizzard. While running around you will likely come across Parchment, Stone Block, and that killer for me, Ore and Diamonds. That has become the limiting factor - I used to think Mist Wood, Deep Mushroom, and Scrap Iron, but now its Diamond that has got me.
You want something tough, try the toy train set on Grizzleheim - requires Earthquake.
In my opinion crafting this house has become harder since Celestia came out; for instance I used to be able to find Nightshade at the Bazaar at a variable price but with a reasonable limit, now the price has shot up, a sort of 1/x relationship between price and quantity available.
Also, wizards and witches attempting to do the Grandmaster craft looking for stone blocks are in the same area in DS, and they are scooping up the Ore, since they have nothing else to do while waiting to change realms. You need 80 Diamonds.
General hints: - The moment you craft something, get it out of your backpack and some place safe, or risk selling it by mistake at the Bazaar! - If you take them out of your backpack you have to maintain a count, you cannot look at the display that comes up when you press 'J'. - A great place to keep the items is in the Attic; since it sorts by name its easy to count how many of each you have. - You can keep Ornamental Stepstones on your dorm room floor. You might have to pick up pets to lay them down. I can vouch that all fifteen fit along with the crafting tables. Sold the bed a long time ago. Guess my wizard never goes to sleep. - None of the recipes are from a vendor 'deep in there', they are all accessible as long as you started Dragonspyre. The same cannot be said for good places to farm for the reagents. - The recipe for the house is in Grizzleheim, just go inside the fortress and take a left. - I read some place you need to take off all your gear to craft it. Not true. You might have to empty out unequipped items though. - I read some place you need to keep detailed notes and plan. I didn't. I first found all the recipes, took a good look what each one required so I knew what to keep an eye out for, then started with the easiest, the Wood Planks, and worked my way up. - Learn to use Wizard101 in windowed mode, because you WILL get bored if you have nothing else to do while waiting to change realms.
Farming hints, besides trying to buy at the Bazaar:
- the Blizzard Treasure Card is dropped by several bosses in Krokosphinx. - Mistwood can be found in Mirkholm Keep on the two islands near the Wolf. If you are on the islands you cannot get into a fight. Both islands have two places to get on/off of them, and the second one is not so obvious. Along the way to the wolf area, along the the walls are several chunks of Ore. Also near the two islands Ore pops up in two places. One can cost you a fight. Up to you. By the way, you need to defeat Jotun to get to this place. - Cattails and Frostflower show up in the lake way back in there by Herkir. - Never found a really good place for Mushrooms other than running around Mooshu. - Do not transmute Scrap Iron, do not buy at the Bazaar, you can find it. - With great difficulty I tell you this: Scrap Iron can be found in the first area of Digmoore Station (Hyde Park?). Just go in a bit, take a right, then go to the end. Found this place on the net. Take a look at the map, it will be more obvious. Along the edges you will find it and Stone Block. Watch out for rats coming up to the center area, they Tower and can take time to kill, especially if your character is Life. Yeah you can kill them but wouldn't you rather change realms? Stay along the edge. Added bonus - you will finally figure out how to do Shock-A-Lock. - I can't remember where it exactly is, but there is a fountain in Marleybone that has gobs of cattails. - If you even THINK you are ever going to do this, stop selling reagents. Or at least get a list of the reagents needed and don't sell those ones. I could kick my self the number of times I sold Nightshade. Or for that matter, Blood Moss back when I started the game.
And the last hint -
If you have more than one account, you can use characters on other accounts to craft items, then sell them at the Bazaar, and have the first character buy them. This is risky, as someone could snatch them right out from under you! After some studying and which character had an abundance of which reagents, I concluded my Life would make the house, and the Death would make the Ornamental Stepstones. Key point is, except the house, all items can be sold at the Bazaaar. Not sure about if they can be put in the shared bank.