Our ancestors were farmers. That's why the Jewish calendar follows the agricultural cycle. As such, they were far more in touch with the land and the elements than we are today.
Yes, Sukkot is about the time that the Israelites wandered in the desert after leaving Egypt. But the major themes of the holiday are all about the harvest: the Arba'at ha-Minim, the Four Species (a/k/a lulav and etrog); the sukkah, the temporary hut decorated with produce and featuring natural materials that enable those inside to see the sky; the unrestrained joy of this holiday, perhaps the happiest of the Jewish year, that comes with the end of the growing season in an agrarian context.
The real message of Sukkot is very simple: get out of the house! Eat, sleep and live in a shack with no central heating and no real roof for a week. That should remind us of our connection to the soil, the rain, the wind, and the rest of Creation. So bundle up and enjoy! Hag sameah.