The Gemara in Yoma tells us that Avraham Avinu knew the entire Torah intuitively. As usual, the Baal Haturim finds a Gematria regarding Avraham that come to, “אף עירוב תבשילים.”
This indicates that he even knew rabbinic law involving cooking from Yom Tov to Shabbat. The simple explanation is that Avraham was on such a high spiritual level, that he knew the Mitzvot his children would observe.
On a certain level, some of the events of our calendar, make sense. It is reasonable that we should have a day of rest each week. This is needed to give us perspective and realize that there is more to life than the physical.
It also makes sense that there be a holiday at the end of a long winter, for cleanliness. A physical house cleaning, combined with cleaning out negative personality traits, seems to make sense.
At the onset of summer, a holiday that renews the special bond between Jews and G-d, is definitely needed. This would be meant to give strength, to avoid temptation.
A holiday in the fall focused on asking for forgiveness, is necessary in case summer was too challenging. A follow up holiday, after a very prosperous harvest, is essential as a reminder, that life is fleeting. Moving into a temporary hut, might drive home this message.
Certainly, Avraham Avinu had his intuitive methods to figure things out. But if we look at where our holidays are placed in our annual calendar, they do make a lot of sense. How fortunate are we to be descendants of our Father Abraham.