You can source the insulation materials from a DIY store, builders supplier, or I find the internet the cheapest option.
The computer and induction hob will use a great deal of power, and you will have to have lots of leisure batteries, and solar panels to power that.
I would recommend using a laptop computer, as they use far less power.
I would also recommend using a gas stove, as carrying a gas bottled, and refilling it, is much easier than carrying the batteries and solar panels.
If you used the laptop and gas, you could get away with just one leisure battery and a single solar panel.