Penny is visibly trapped in the maser beam, shouting unheard as she beats against the impenetrable beam before disappearing. When she's brought back, she has no memory of being away, or of being trapped in the beam, or of being startled and driven back upon the maser launch pad by electrical explosions from the alien machine.
Will meets plenty of townsfolk who know about the tragic loss of the Robinson family, presumably from media coverage. Yet apparently none of those reports included pictures of the Robinsons, as no one seems to recognize Will as one of the Robinsons.
The Robinsons are lost in space. The Tauron transporter machine works on a completely different system than what the robot can understand, yet under Will's directive the robot can directly beam Will across the galaxy to Earth. Three hours later - and despite the rotation factors of two different planets - the robot is able to have the machine bring Will back.
It is often considered to be a Goof that the town Will lands in is somewhat backward in appearance and that no one recognizes Will as one of one of the Robinson's. This backwardness of the town is necessary for the plot to work. Because the town is somewhat remote and cutoff from the rest of the world, it hasn't progressed like every other town and has been left behind. This backward and remote town also helps explain why the townspeople, who have heard of the Robinsons, do not recognize Will and therefore do not believe his story.