Factual error: Science Officer Tilly calls the planet Trill a "very big" planet. It has an area of 500 million square kilometers. But that is not so large a planet. The Earth has an area of 510,100,000 square kilometers. So Trill is slightly smaller than Earth. Not really a "very big" planet.
Factual error: In several different episodes characters are escaping on foot to Canada, as evidenced by Ontario license plates. But the show is set in New England, and the only way to get to Ontario through the Eastern United States is by crossing a major body of water: The St. Lawrence River, Lake Ontario, The Niagara River, or Lake Erie. You can't walk there.