I just received my updated rulebook and scenario book today from the 2nd kickstarter. Can someone point of the main differences between the new books vs. the old ones? Is there any point to me keeping any of the old materials? Any help is appreciated.As far as the scenario book differences go, the official second printing change log is probably the best reference. In short, Cragheart's suggested items are changed, some scenario setups are tweaked for various reasons, some typos were fixed (most especially the treasure number for scenario #10 was incorrect in the first printing), a few things were clarified, and unlock and requirement related stuff was switched around to fix some issues.
Rulebook changes should all be clarifications, typo fixes, or differences related to component differences. As long as you've been keeping up with the FAQ, I don't believe there are any meaningful mechanical changes to the rulebook.
You should be completely safe to toss the first printing rulebook if you'd like. As for the scenario book, at the very least you should check the change log to make note of the changes that have effects beyond the single scenario. In particular, there are changes to global achievements that you may need to be aware of depending on the state of your campaign.