Sled/packing dogs?

I am planning a long, long hike---possibly across the USA. I'd like to get a dog for companionship and who can perhaps pull a backpack---(and maybe me) during 25-30 mile a day hikes. Where do I go to talk with sled dog owners, what do I look for in a dog of this sort, and is there a better breed than a Huskey for this sort of thing?