Borgie

I can help a bit with the part about determining if you're indoors.  You need to do this when it's cold outside:

Open the Character Window, and look at your "Hunger Rate" under stats.  Sometimes it takes a few seconds to update.  If it's above 100%, then you're not "in a room".

But make sure armor/offhand item are not affecting you, and that it's actually cold enough for this stat to be modified.

Another note: in order to find my problem above, I split the room into halves with dirt blocks until I found where the problem was.

If you chisel a stair-block into a ramp using the smallest block size the motion is actually quite smooth.  It does take a long time, and destroys your chisels.  You also cannot sprint up these stairs.

I've destroyed two filled barrels by accident while chopping wood wall blocks near my barrels.  Clearly I need to be more careful.

However, with an iron axe the chop speed was immediate.  Maybe if the barrel has content we could require additional time to allow the user to stop.

When using a chiseled block, the room does not count as a "room", and your food rate still increases when cold.

I'm not sure how difficult this one is to manage, given that chiseled blocks can be any shape.  I ran into an issue with a block I chiseled by mistake, but didn't actually modify it.  Because the block looks identical to non-chiseled blocks, it's very hard to track down.

If not possible to calculate rooms with chiseled blocks, maybe an overlay/dev tool to display valid room-blocks could help.  Seems like slabs are valid blocks.