I would not take a laptop backpacking, but if I had to, I suppose I’d probably try to use something small and ARM based to get better battery life (but, more likely, I’d just use a phone instead which is smaller and waterproof).
It kinda depends on what exactly you need to do though. Can you provide us with more details? What do you need the laptop to do?
What kind of backpacking are we talking here? Going into the wild for weeks or months at a time? Going on a little vacation through cities in Europe?
That seems more likely but we won’t know for sure until they tell us.