Frostpunk: Edition

Whether you decide to save New London or not, it will be near impossible without the help of the other settlements. In order to get their help, you will need to finish the safe supply route with each, including the upgraded depot on their end. Whether you choose to let New London fall or save it, each settlement will provide a key resource and leave you only with one.

On my first playthrough, I was unable to complete the safe route with Children's Mine and wasn't quite able to make up the shortfall. The next playthrough I had all routes completed and it was much easier completing my objectives with New London.