What sort of gear were fur trappers/ explorers using at this period? I'm especially interested in the type of packs they had and their sleep systems.
I don't know that the fur trade was really off the ground in the 17th century. The Hudson's Bay Company wasn't formed till 1670.
http://www.canadiana.ca/hbc/intro_e.html
Pierre Chouteau Junior wasn't even born until towards the end of the 18th.
http://en.wikipedia.org/wiki/Pierre_Chouteau,_Jr.
I think in general the answer is likely to be that people started off by taking what they were used to back home and replaced it with what was locally available as it wore out or as they began to appreciate the particular qualities of what native peoples were using. That was a two way thing, of course. There's a (fairly early) painting of American Indians dancing (Menominee, I think) and while they're brandishing wooden war clubs (soon doubtless to be replaced by Birmingham-made hatchets) they're all wearing calico shirts.
The European fibres for clothing (and just about everything else) in the early modern period were wool and linen. Cotton had to be imported and didn't take off in Europe until the Industrial Revolution brought new techniques for processing it. In the wilds I think you probably slept wrapped in a woollen blanket.
I think, as has already been said, that haversacks (from an old word for oats—one of the Yorkshire Regiments was known as the Havercake Lads on account of the oatcakes traditionally eaten in the area) used to be commonly used in the past as also snapsacks—picture here:
http://www.karlrobinson.co.uk/other_bags_sausage_bag.php
I don't know that you'd get that much in either sort of bag, though. The voyageurs are known to have used tumplines round packs.