The beginning was hilarious: "There's a missile coming straight for us...let's sit tight, and not move out of the way."
And they were so trusting back then! "Here, Will, my 10-yr old son...stay here alone with this strange man we don't know from anybody for a few hours. Heck, maybe you and your teenage sister should go off into the cosmos with him."
And then there was Hapgood complimenting Judy on her mother's space pie.
Another point of interest: in this early episode, there were still trying to maintain some mystique/menace around the robot...dramatic threatening music plays when he enters the scene.
The TV fascination w/ westerns and "country folk" was still in full swing at this time; "Wagon Train" was in its last year, but "Bonanza", "Gun Smoke", and even "The Beverly Hillbillies" and "The Andy Griffith Show" were still going strong, and it seems LIS couldn't resist shoehorning a cowboy into their sci-fi (syfy?) millieu. Not a whole lot happens here, this one was more of an introspective episode, but there was some good character acting and family sentimentality. And I think that when I was a little kid I would have thought the spore monsters were pretty cool.
One thing I remember fondly from LIS is the way the epilogue always tied into the following episode, even though the episodes themselves were largely self-contained and unrelated. That's a cool idea TV should revisit.