I noticed on one of my multiple runs that it seems you burn out faster if you C'n'R than if you do standard rolling... I haven't actually tested this, but I'm pretty sure it happens...
Anyone else have any theories?

Hmm, i'll check that out sometime. Charge N roll is necessary for good records though.

All I know is it seems like you burn out faster when you are bigger.

that I have definitely noticed, it's a lot hard to keep the flame going when you are bigger

You naturally cover more ground whenever you CNR, so it would make sense that the flame would burn out faster if you CNR. I *think* it may burn out faster but I'm not entirely sure. And I do agree that it is harder to keep the flame going when you are bigger as there are much less items to roll up when you get so large. What I usually do to keep from burning out on Campfire Large is that I keep a "reserve" of wooden items, such as the logs on the bridge or the fencing around the woodstack. The great thing about keeping the fencing as a "reserve" is that it is around the goal, plus the cliff that its on is in the center of the stage, so you can roll around, gathering up the fence portions at a time (keeping that passionate fire alive and burning) and getting any items that you may have left that aren't too far from the cliff before rolling up the woodstack.