Heat will probably be the last resort and yes, the valve core will be removed if we do that.  It looks clean in the stud hole.  It's where the rim pilot hole sits on the hub that it's visibly full or white crap. Lots of sledge hammering.  Air hammer on rim and hub.  Splintered some wood blocks hitting on the rim.  Chain tied to forklift and rim and tugged the trailer sideways.  Drove it around with the nuts loose.  Not budging.  It's the inside rim, outside is off.