Other than the fact that it's a great read, there are several reasons why Ernest Callenbach's 1975 novel Ecotopia is a motivating force for our travels
Oneness with Nature
In the novel energy demands are enormously mitigated when roads are removed, urban infrastructure revised so that people live within biking or walking distance from most of the places they need to go. For longer distance trips, there are electric trams that crisscross towns and a highly efficient high-speed train that connects the country. In this way they are able to supply 100% of energy demands from renewable sources.
All packaging, single-use items, and other throw-a-ways are not only biodegradable but beneficial for the soil. Products are engineered to be simple and repairable. Instead of mining Earth for more resources, the ones already in play are reused.
Instead of being drafted into the army, citizens are drafted into conservation and preservation camps where they learn how to properly care for Earth's natural systems.
Progressive (as well as some old-school) Values
Ecotopians are depicted as creative, educated people with real-world skills like farming, building, and teaching. They repair their own items or, if not repairable, use their ingenuity to build new useful items with the resources extrapolated from the old item.
They value creativity, equality, and being in good health.
They value friendliness but aren't afraid to be impolite if it means being honest. They value meaningful discussion, living with integrity, and being playful.
The novel is a well-thought out example of how a large society could flourish and grow in a way that doesn't exhaust the Earth of all her resources. It's characters are connected, intelligent, and fulfilled.
It's exactly the kind of society these writers want to be a part of.