>>1632222Much. Unless you are an experienced winter traveller you are going to be putting yourself in some danger.
You will cover much fewer miles than a normal season hiker so it will take you longer and cost you more money.
Logistically you would have to do a fair bit of research as hostels, shops, and even roads may be closed. All most all the info you will find about the AT is aimed at people who are hiking in peak season so you would most likely have to get in contact with people who have hiked it in the winter to talk to them.
The whites could be lethal, so you'd have to be comfortable that you can make sensible choices when faced with less than ideal conditions.
If you haven't travelled much in the snow I would suggest a realistic plan could be to section hike a few bits over the next two years to make a solid plan then look to thru.