Thanks for reaching out!
That sounds like quite the trip you have planned! When I was living in Fairbanks, Alaska I had the great honor of helping support (with the logistics of storing gear for the expedition) Andrew Lock's two attempts to ski across the Brook's Range with Neil Ward. I remember talking with him about his training regime and it sounded very familiar to what you are doing. Good on you!
In terms of calculating 'kilojoules' I am assuming you mean calories burned (likely what we refer to it as here in the states). Is that what you're looking for? How much energy you are burning during your workouts? We have some fitness watches (and there are even some rough calculations you can find on the internet, depending on how accurate you want them to be) that calculate calories burned by using your heart rate and personal information such as height and weight. Please let us know if that is the kind of information you are looking for or if it is something else.