I am wondering if most of the high EE items (armors, weapons, charms) come from random monster drops, or if more of them are crafted through transmuting. Can anyone offer some insight?

Kill more = more chances to find something good

It used to be that most of the 200+ee items came from muting but that has changed since it became a skill. Now it's just all about blind luck, you might find something super godly tomorrow or it might be in 3 years. Just keep on playing and you'll find something good eventually.

Lol. I guess I should keep killing. Is there like stipulations? Like If I'm 18 and I am killing level 18 mobs, do I have a better chance of getting better items off stuff my level, or would it be the same if I ran around slaughtering level 1's?

the maximum item level of a monster is 10 levels below it's level

eg, the monster has to be level 45 for level 35 items to drop

also, item drop rates decline rapidly when you kill under your level (50% per level i think)

If you well an item, that also helps.
(Putting a blank item into the Well of evil and successfully killing the monsters)

Beware! These monsters are a lot more difficult.
Well of Evil

If you are lower than the level listed on the item, and you throw the item in, you will fight a monster one above the level requirement of the item.
If you are above it then the mob is just +1 your level.

PM me if you have any more questions.