Just write the fun parts. Take a science fiction premise — that evolution ran differently on an alternate earth giving rise to kaiju (Godzilla and company, I didn’t know the term before I had heard of this book) — and just write the fun parts. That’s The Kaiju Preservation Society. The parallel earths, two among presumably …
Al Singh
Doug Merrill
Doreen Sheridan
John Pitzel
Lars N. Goldschlager
Laura Eilers
Professor X
Robert Maedgen
Sylvere Ap Leanan
The Shire