What favour did Sue want from Ann in All My Sons?

In Arthur Miller's All My Sons, Sue Bayliss, a former nurse, is the wife of Dr. Jim Bayliss, a physician in private practice. Dr. Bayliss's practice is going well, and it pays well—which Sue likes—but Dr. Bayliss is becoming increasingly dissatisfied caring for well-paying hypochondriacs. He would prefer to do medical research, but it doesn't pay as well as private practice, and Sue is very much set against having his income diminished and having her comfortable suburban lifestyle changed for the worse.
Sue is concerned that their neighbor, Chris Keeler, a somewhat naive, idealistic war veteran, is influencing her husband to give up his private practice to pursue a career in medical research.
Chris has invited Ann Deever, a young woman from the neighborhood who moved away, to come back to the neighborhood so that he can ask her to marry him. He does, and she accepts his proposal of marriage.
Towards the beginning of act 2, Sue and Ann are together in the yard, discussing the upcoming marriage and the trials and tribulations of married life, when Sue asks Ann for "a small favor."

Sue: That's why I've been intending to ask you a small favor, Ann. It's something very important to me.
Ann: Certainly, if I can do it.
Sue: You can. When you take up housekeeping, try to find a place away from here.
Ann: Are you fooling?
Sue: I'm very serious. My husband is unhappy with Chris around.
Ann: How is that?
Sue: Jim's a successful doctor. But he's got an idea he'd like to do medical research. Discover things. You see?
Ann: Well, isn't that good?
Sue: Research pays twenty five dollars a week minus laundering the hair shirt. You've got to give up your life to go into it.
Ann: How does Chris . . .
Sue: (with growing feeling) Chris makes people want to be better that it's possible to be. He does that to people.
Ann: Is that bad?

Quite simply, after Ann and Chris are married, Sue wants Ann to take Chris far away from the neighborhood and far away from Dr. Bayliss, so that Chris will stop putting idealistic, humanitarian ideas into Dr. Bayliss's head, and Sue can maintain her lifestyle.