In another quirk of fate, actress Susan French (Elderly Elise) was born in 1912 (same year as the film) after her parents honeymooned at the Hotel del Coronado, which is where Richard Matheson originally intended the movie to be filmed. He wrote the original book, "Bid Time Return", while staying at the Del. Unfortunately, the Del is surrounded by modern condos, which special effects of the time weren't sophisticated enough to remove, so someone suggested the Grand, built the same year as the Del, and the rest is history.
At the time "Somewhere In Time" was filmed, no motor-vehicles were allowed on Mackinac Island, so the entire cast and crew made good use of bicycles. The island still has this policy, even today ... which makes it all the more a perfect 'get-away' resort to visit.