Like many others, we finished a Hurtigruten cruise in Kirkeness and had pre-booked the Snowhotel from Australia. Hurtigruten run busses to the Snowhotel for other tours, such as dog-sledding, so we had transport from the ship. The property is charming with reindeers on view, dog sledding to watch or partake in (we'd done dog-sledding in another port) a cosy restaurant (Gabba) and of course the Ice Hotel.
Whether you choose to stay or not, the hotel is awesome and I would absolutely recommend going to see the 21 or so differently themed rooms which are created at the start of every winter. The carvings are so well done and I wondered through taking pictures of the different scenes, complete at times with crackling fires (achieved with lights). If you weren't in -4, it'd be easy to see a picture and think it was a cosy hotel room with the deer skin pelts on the beds.
To help with planning, the hotel runs a shuttle to the 'downtown' area and there's a museum on the way which we wanted to see. check the times it closes tho as (from memory) it was around 2pm and we got there at 1.50 or so. Kirkeness itself - well at least in the dark and cold of winter - didn't offer much by way of sightseeing and wasn't an overly pretty town either (just in our opinion). If I had my time again, I'd stay at the ice hotel in the cosy guest lounge and read a book or take advantage of the excellent wifi.
Any-hoo, back to the stay. As mentioned in other reviews, the staff are all lovely and multi-lingual and everything was taken care of (ie cases from the ships to the hotel). We met for instructions around 5pm and from there to dinner, which was delicious. (Dinner is served in a warm restaurant attached to the ice hotel, as is breakfast, also delicious). All instructions are provided and essentially you sleep in a balaclava and in a mummy-type-sleeping bag. Agree you would be best not needing to unzip in -4c for a bathroom stop however we didn't see the curtains across the entrance as any privacy issue. No one is up and walking around! Perhaps if you're easily wakened, take your pods in with you and listen to whatever makes you happy. There are shower facilities and places to leave your luggage and if you can't make it through the night, the aforementioned lounge which is warm and cosy, beckons.
One thing to mention that was for me, I struggled with claustrophobia being so covered up. My husband and many others slept super well though. If I could turn back time, I'd definitely tour the ice-hotel but I'd stay in the cabins tho' this is no reflection on the way things are run or the facilities provided. Be aware too that there are no alarms for Northern Lights and it's unreasonable to think you'll be unzipping and popping out to look so cabins would be a better option if seeing the lights is your goal. The snowhotel do run night tours for this as well although on the night we went, while seeing the Russian border, we did not see any lights due to cloud coverage.
So I left a long review in the hope that this helps you make the best call. I consider it an unforgettable experience and very well run.