http://revach.net/article.php?id=4768

Section: Moadim   Category: Succos
On Succos We Learn To Hide From Yom Kippur

There are a number of reasons given for the connection between Succos and Yom Kippur and why they are so close together.  Some say that Galus is Michaper and therefore if we have been given any harsh punishments,our Galus and leaving our house should be a kapara instead.

Rav Shimshon Pincus answer answer that after Yom Kippur we are Baalei Tshuva.  Like any Baal Tshuva, after being bitten by the bug we must take measures to make sure that it lasts and we don't quickly revert back to our old ways.  The biggest challenge is when we go back to our old surroundings and hang out with our old friends.  They certainly won't take our change in stride, and after the initial ridiculing, many are bound to just throw in the towel and go back to their old self.  The best course is to leave your social network and find a new one.  Similarly after Yom Kippur we leave our home and our lives and go live with Avrohom, Yitzchok, Yaakov, and all the Ushpizin who encourage our change.

Another possible explanation may lie in the minhag to say L'Dovid Hashem Ori until Hoshana Rabba as it says "Ki Yizpineini B'Sucoi B'Yom Ra", because Hashem concealed me in his Succah on the evil day.  This is a remez to the Succah.  Maybe the lesson here is that often during the year we will find ourselves in a tough spot.  No one has a perfect year.  But Hashem teaches us the secret to making it through the year no matter what our fate has in store.  "Hide in my tent!  Conceal yourself in my shadow."  When we are with Hashem, no matter what is going on around us life is always perfect.  In good times and in troubled situations the best place to be is near Hashem.  It doesn't matter what is going on outside or what your Chasima was, inside with Hashem it is always pleasant.