This is a fascinating idea, a giant spaceship offers a ride to anyone who wants to come. Be on a seashore at a given time, and you come along for the ride. A lot of people take the spaceship up on the offer, for a lot of reasons. The beginning of the working out of all their combined stories is the novel. The title is perfectly chosen. In a way, it's similar to the recent movie, "The Way".
One passing observation of Sinclair's stuck with me. The measure of our sins is the totality of the pain they cause others. That's a non-obvious criterion, but it seems right, somehow. Kill someone and you cause them great pain for a short time, but you also cause longer-lasting, less-intense pain to all the other people you involve, their family, your family, the EMTs, the police, the judge, jury & prosecuters, if it comes to that. That idea alone was worth the read.