I'd just start with Skyrim. They aren't "sequels" to each other storywise(outside of the general history), so might as well.
The dragons as far as I know don't scale, and the bears and trolls and shit do. So while dragons tend to level off after a few, other encounters seem oddly difficult in logical comparison.
Of course, I annihilate dragons, bears, giants, and trolls, so whatever, mage ftw. :fuckyeah: