I turned an old 14 ft enclosed work trailer into a shack, worked great for me. I remove the tires if i want it a little closer to the ice.
I use a cheap chinese diesel heater and it works great. Had wood stoves in previous ones and will never go back.
I built from the frame up and insulated everything including the floor. Hole sleeves are required to keep cold air from coming up and your holes freezing.
PM if you have any questions, this one worked out so well, I will be selling it to make a bigger one.
Interior shot, before holes were put in the floor.