There are several characters in To Kill a Mockingbird who benefit from being isolated, including Miss Maudie, Jem, Scout, and Boo Radley. These characters are isolated from the typical racist thinking and actions that seem to seep into every other character and situation in the small town of Maycomb.
Miss Maudie's isolation allows her to work in her yard and have her own thoughts and opinions about things without judgement. Her isolation is self-imposed, but she enjoys the freedom. She isn't married, which gives her the opportunity to think for herself instead of restating the opinion of her husband, which was often expected of women.
Jem and Scout have the isolation associated with being the only children on their street. They are young, and are afforded carefree summers of isolation playing in the yard with Dill. This isolation protects them from hearing a lot of the gossip and ugliness that is happening all around them in the town. Their father's education is another reason for their isolation. They don't really fit in with the children of the uneducated townspeople. Their lives and experiences are different, so their thoughts and opinions on Tom's case and innocence differ greatly from that of their classmates.
Boo Radley is probably the most obviously isolated character in Maycomb. He hasn't seen the light of day in years, and he just watches over Scout and Jem from his window. His isolation, even though initially forced on him by his bad choices and worse relations, resulted in him being disconnected from everyone and everything in the town. Over the entire course of this novel, he only did one thing: protect Jem and Scout from Bob Ewell. Had he not been so isolated, he would not have witnessed the attack. In Boo's case, the isolation was beneficial because it allowed him to save the lives of his neighbors.