This question is asking for a subjective opinion, so you are free to defend either side of the argument. While Kelton, Jacqui, Alyssa, and Garrett do work together for survival, you could certainly make an argument that the characters would have been better off trying to survive as individuals. The strongest case for that argument would be Kelton. He's been raised as a survivalist by his family, and his family made sure that their supplies were adequate for their family. By deciding to help Alyssa and Garrett, Kelton is putting extra demand on his limited supplies. He might be better off by himself. The same argument could be made about any individual surviving. More people means more mouths to feed.
Conversely, more people might mean greater security. There is strength in numbers. "Bad guys" are less likely to try and take advantage of a group. A group is also harder to surprise, because multiple group members means multiple sets of eyes watching in multiple directions.
A group also allows for much greater security at night. One person can stand watch while the other people sleep, and that physical rest is invaluable in survival situations. Multiple people also aids in problem-solving situations. Finally, if a person is surviving as an individual, injury is a huge problem. A broken leg could be a death sentence, but a person in a group can still be provided for as they heal.