It was mostly luck, with a bit of remembering roughly how far the damn things were from spawn in the other worlds.
I decided tonight to just get it over with and build the portal. It's not a direct path, but I needed to find an area in the Nether that looked like it went all the way to the top bedrock. That way I wouldn't be building walkways and spending tons of loot right before the wipe. I tunneled up to bedrock, and after that it was a pretty easy (albeit long) path to get out there just clearing out netherrack.
I trekked 4 Mooshrooms back from the island and built a Soup Farm next to the Meat Mart. Please, no shearing (they'll turn into normal cows) and no killing. But, if you want to breed some for your own or just to let some loose in the wild, have at it.
