Improvised Weapons and Hurling... When Things Get Ridiculous

I'm sure I'm not the first person to ask this dumb question.

So, under the improvised weapon rules, you compare an object's relative size to determine its damage. So a barstool might do 1d6, whereas a heavy plant might do 1d8. A table might even manage 2d6, if it's a good, sturdy piece of furniture. A thrown improvised weapon has a range of 10 feet.

My question is how do you deal with characters who have prodigious Strength scores, lifting capacity, and the ability to hurl huge items at their enemies?

Say, for instance, you have a barbarian alchemist. You get Throw Anything for free, and you take Catch Off-Guard as your 1st level feat. You now have access to extracts, mutagen, and Rage Powers. So you start at Strength 20 (high, but not impossible). You drink a Strength mutagen for 24, then you Rage for 28. That's a 400 pound light load. Then you add on the effects of Ant Haul, tripling your light carrying capacity to 1200 pounds.

The first question is, since you can lift and carry something that heavy with relative ease, can you throw it just as easily? Ant Haul wouldn't increase your throw weapon damage, obviously, but it would give you the ability to pick up something much bigger than you normally could. Still, how to you determine the damage of something that big? Especially if you combine it with something like Hurling Charge?

Put another way, how do you determine the damage of flinging an ox cart at someone? Or, if there is an errata that clarifies you can lift but not throw something with ant haul, how do you determine the damage done by what is essentially a decently large tree trunk flung like a javelin with the 400 pound limit?

Or, because we're dealing with weapons, does this fall under the age-old answer of "you cannot wield anything bigger than a large-sized one-handed weapon without a special feature saying otherwise"? And, if that were the case, what happens when you become Large-sized via something like Enlarge Person? What is the biggest thing you could pick up, and fling?

Appreciate any and all responses, but if possible please include page numbers, or links to a source that backs up your answer. Looking for if this was answered in the rules, not how a particular DM would rule it by their own judgment at their table.

I'd make use of the rules for Rock Throwing, at least for the damage dealt (since it's still going to be an improvised weapon).

Looking through giants with this ability, it can be found that Large giants, like hill or stone giants, who can throw Small-sized rocks use 1d8 dice for damage. Huge giants that use Medium-sized boulders, like taiga giants, use 2d6 dice.

For an item that isn't actualy made of stone, estimate its weight and choose an appropriate size of the stone.

If an item has lower hardness than stone, you can make it deal less damage.

The rules for falling objects might be relevant at times. And the full-round action normally required to throw something two-handed (& maybe the two-handed thrower feat.)

It doesn't directly answer your question but I think there are situations where these may be relevant to you.

That is a new rule I didn't know. Was always under the impression that throwing 2-handed weapons was the same as throwing a one-handed one. I shall remember that.