In reply to crayefish:
Northern part of the kungsleden is dead simple and fairly flat. Southern part is a bit more undulating and interesting, and not so well used. None of it could even vaguely be described as an expedition. It has marker posts all the way along it, and there will usually be snowmobile tracks. You can access it from a train/snowmobile/bus at various points - this is Sweden so the roads are either kept open or they just use snowmobiles instead..
We were there in mid march and had to sit out storms on a couple of days otherwise the weather was similar to scottish winter, but a bit colder at night. Think -20 was about as low as it got.
Plenty of comfy huts easily within a days walk apart; most with blankets and fuel, and every other one with a warden and a shop, so taking a pulk and camping is just stupid imo. The nights are still long, your tent will be frozen solid until the sun comes up, and you'll have to carry loads of fuel to melt water. Nothing hard about it, just stupid.
We used snowshoes as my partner wasnt confident using skis with a pack. In fact she would have been fine.
Nordic touring skis would be faster but only if you know how to use them. We overtook a lot of people who didnt.
The stf site has loads of info -
https://www.swedishtouristassociation.com/
Why do so many people have to claim that their holidays/trips are for charity? Getting to northern Sweden isnt cheap, so donating the cost of the trip would probably be of much more benefit.