The Mitzvah of Sukkah

Hello Rabbi, happy holidays.
 
1. Going on a trip. Is there a fence for travelers who are exempt from the sukkah?
2. Regarding the above, what is the law if I just went to eat pizza in the nearest city, is that a roadblock? What exactly is the definition?
3. I am used to sleeping in complete darkness (I find it annoying to sleep with the light on). When all of us siblings sleep together, my little brother is afraid to sleep in the dark and therefore doesn't let me turn it off. Am I exempt from sleeping in the sukkah?
4. On hot days, is a person who is used to sleeping with an air conditioner required to install one in the sukkah, so that he doesn't regret it and get rid of it? And what about a person who didn't install one in advance, will he get rid of it in the event of a fever?