According to Halacha, on sukkot Jews should eat whatever food they are going to eat in the sukkah. My question is, is there any length Jews have to be from a sukkah so they are Petur from the obligation eat in it? What is the size of distance Jews have to travel that they don’t have to go out of their way to eat in the sukkah
It is less about the distance, and more about whether there is a good reason to travel knowing there won't be a sukkah.
Those who travel for pressing matters (business, mitzvah) are permitted to eat outside a sukkah during the day (OC 640:8) if they don't find one. The same is true at night although they have to try hard.
There is a discussion in the poskim whether a day trip for fun is allowed should there be no sukkah.