"Up to this point," means through chapter four, so you can probably use anything from chapters 1-4, although you probably want to use mostly details from chapter four.
Chapter four takes place in Crooks' room. You have Crooks, who appears sympathetic because of the prejudice and segregation he suffers from. He is also sympathetic because of his reaction to the dream of owning their own place that he hears about from Lennie.
Lennie, of course, is also presented sympathetically. He, one could say, is not smart enough to be influenced by society, so he talks to Crooks like an equal.
Candy, too, is sympathetic. He, too, has a marginal place in society and dreams of something better.
All three of these characters are misfits, isolated in one way or another from society. Any of them are characters that you could like.