You are fortunate that you have the luxury of easy consistent water access. That makes a big difference with how far you can go and weight reduction overall.Yes. I have done some hiking in places where I had to carry all water I needed, and it does indeed make a big difference.
Since we put a lot of our stuff up in bear bags at every camp, there is a lot of packing and unpacking every day.Right. For whatever reason, Finnish bears are very shy of people, so there's no need to worry about them. I've only once come across a bear in Lapland, and by the time I saw it, it was already running away fast.
IMHO, when hiking, the simpler the better.Right. My problem is that besides scenery I also want to photograph wildlife, including birds. The 70-300L is a compromise for that: small enough to carry easily, long enough to be useful - although longer would of course be better. (I have carried the 100-400L on occasion, and the moment I find myself considering dragging my new Tamron 150-600 on a hike... probably won't, though). Otherwise, I might take just the Ricoh GR (then I'd probably get the wide-angle accessory for it though).
So that's why I am trying to really think the whole "better camera" thing through. Because the group loves my pictures regardless, even if they're just from the little rugged D20. I'm the only one who really appreciates/enjoys the IQ difference and superior handling of the SLR.