Galileo7 was talking about the original unaired pilot, which did not include Smith or the Robot. When the show went to series, new material with Smith and the Robot, plus other new content set in the lower deck, was interpolated with the pilot footage, with most of the original pilot's contents spread across episodes 1, 3, 4, and 5 of the series.
In the original pilot, the ship was knocked off-course by the meteor swarm rather than sabotage, and it drifted for years with the crew in stasis until it finally crashed on a planet. The family built a homestead around the wrecked ship, then abandoned it when the planet grew too hot and they had to head for cooler climes. The pilot ended with them reaching a new shore and offering up a prayer for their survival, with aliens watching them from behind the foliage. In the aired episodes, the structure of the story was changed so that the party returned to the ship at the end, so that they could continue using the sets. (Also Dr. Smith and the Robot had stayed behind because they weren't in the original pilot footage.)