If a shabbat service does not have a baal koray, someone who can read from the torah scroll, is it halachically acceptable to have someone read from chumash and follow along from the scroll, as opposed to not having a torah reading at all?

Reading from a Chumash is regarded as reading by heart, and one is not Yotze Yedei Chova with it. It is advisable in such a case that one person reads correctly from a Chumash and another repeats him from the Torah scroll. Another possibility is to learn a sign language of the reading and that can also be used. Rabbi Yitzchak Grinblat