[REW]

You might consider the use of steel for the skids.
If you use the right size I beams and cross bars - the weight will be little different than using wood beams and 2X4's and it will be immensely stronger.

This idea of using the steel skids and cross bars come from all of the northern resorts. They move the houses a lot - simply hook up a chained up truck - rip it out of the ice and off the ice they go. If the shack were made with wood skids, the skids would get ripped apart every time the shack was moved.

Another pointer from checking out the resort shacks --- you can use 2 inch thick foam for the walls - and use contact adhesive to glue on 1/8 " paneling or even 1/4". Very light, but because of the "stressed skin" construction - very strong. This is the principal that makes airplanes work so well.

Making the floor the same way - on top of the steel cross bars, will result in a warm floor, but plenty strong for standing.

Grab a piece of paper - draw it up - and have a go at it.

Another nice thing to do - is to make it so that it can be bolted together. That way - in the spring, you can take down the house in sections - and store it flat. Lots less storage space required.

Take care
REW