I spent hours updating KragenBars for the changes to all of the classes represented. During that time I ran with KragenBars only and did not experience any crashes. However, when I activated BuffBars and did something as simple as attack the training dummy in Eyes & Guard Inn I crashed out. So I'm pretty confident that KragenBars isn't causing a crash. Which leads me back to my original assessment of the hook to the BackPack (I know both BuffBars and Travel hook to the backpack because I checked the code of each). Looks like Turbine might have broken that function even worse than before... at least before your LUA backpack was just inaccurate... now it looks like I completely kills LotRO.
Maybe if I get some time I'll try seeing if I can disable the backpack hook in BuffBars without killing the plugin altogether... then see if I still crash out. If not, then Pengoros won't have to change that much