There are 11 layers at Troy! Some are built during periods of development, others due to destruction.

Tin was imported from a lot of Europe, even from as far as Britain! Britain, Brittany (France), the Iberian Peninsula, Germany/CzechRepublic, and the Balkans all traded tin to the Mediterranean. Amber came from the Baltic region which is just as far! It's wild how far goods moved in the ancient world! (^(Tutankhamen's tomb has amber from the Baltics.))

What is less clear is the people side of all of it. We have some evidence for ships carrying trade goods, but it can be hard to assess if most of the trade was via direct, long distance trade relationships or was simply passed through many areas over time. (e.g. Changing hands 100 times from one place to the other) Most likely there was all of the above.

I don't have a good map with dates for each city, but I do have dates on some notable cities from my notes! I'm in a class on the Ancient Mediterranean.

In general we can tell if a city was attacked or not through archaeological evidence. Cities like Troy (VIIa)*, Gibala, and Ugarit were considered razed because a lot of arrowheads were found embedded in walls & buildings, skeletons show signs of non-crushing violent injury and there is evidence of widespread fires.

In contrast cities like Troy (VI)* and Tiryns were likely destroyed by earthquakes because skeletons show signs almost exclusively of crushing injuries, buildings are destroyed but without any evidence for weapons or (significant) fire, and the specific destruction pattern for the buildings. ((Invaders don't shake blocks out of all of the buildings in a city))

*Troy VI and Troy VIIa are both in the same location, but they're different archaeological layers. i.e. Troy VI was destroyed by an earthquake, but the people rebuilt after the destruction.

This is one of my favorite periods in history and I too question what was going on in the surrounding areas beyond the Mediterranean, especially up in Europe. We know that there was trade coming from Europe such as tin and amber, and the amber was coming from pretty far north so at least some people up in Europe knew about these Mediterranean cultures!

I'm in a class on Ancient Mediterranean history right now and the main issue with the Dorian invasion hypothesis is that there is no archaeological evidence for Dorians specifically.

If Dorians invaded they'd presumably bring Dorian weapons and tools, but we haven't found any dating to that period.

That's part of the mystery that I love. Some places were clearly razed by an army, others seem to have been destroyed by earthquakes, some had the elite section of the city destroyed but the rest relatively untouched, iirc one place had a single temple preserved. Sure seems like a hellish time to live in that area!