I want to get the history of Vulcan from the source instead of from Memory Alpha and other secondary sources.
Is there a sequence of key episodes (all series included) which I can watch to pull this off?
Enterprise season 4 episodes 7, 8 and 9 provide a little bit of history on the Vulcans.
However for the most part I do not believe there are any episodes that exclusively cover Vulcan history
In the original television series
In Balance of Terror Spock explains, that
Vulcan, like Earth, had its aggressive colonising period
In All Our Yesterdays McCoy and Spock went back 5000 years in the past.
Spock becomes more and more savage. They realize, that Spock reverts to the state of the collective self of that point in time on Vulcan, where his "ancestors are barbarians. Warlike barbarians." McCoy adds that they "nearly killed themselves off with their own passions."
In The Savage Curtain Kirk and Spock meet Surak, the most important historical figure in Vulcan history.
"The greatest of all who ever lived on our planet, Captain. The father of all we became", "revered as the father of our civilisation." Surak's teachings of logic and unemotionalism transformed Vulcan from savage and warlike into civilized and peaceful. Surak explains "We'd suffered devastating wars which nearly destroyed our planet. Another was about to begin. We were torn. But out of our suffering some of us found the discipline to act. We sent emissaries to our opponents to propose peace. The first were killed, but others followed. Ultimately we achieved peace, which has lasted since then."
That's about it. In TOS we get to see and hear more about what the Vulcan philosophy, culture and character is, we learn little about Vulcan history. There are no episodes which deal exclusively with Vulcan history. And you don't have to watch these episodes in a certain sequence, since
a) all of the information given in these three episodes is kind of the same, except that Surak gives us some more details and
b) all of the information given is without mention of a specific time period (from date x to date y) or specific historic occurences which we can only understand when we know what had happened before.