After a somewhat mediocre run of episodes starting off, the series pulls together at this point by basically establishing that the crew is a family. Chip and Joshua are brought in with the previous episode, and even though Chip is shuffled off for this episode, his presence is still felt. You also get Pickalong, the new recurring cast member. You finally get the impression that there's an actual crew rather than a bunch of faceless guys toting bales in the background.
And this episode couldn't have worked without a stronger portrayal of the crew, since they go behind Grey's back to smuggle Joan onboard.
The weak spot in the cast at this point is really... well, Burt Reynolds. You get the impression he left the show not because of arguments with Darren McGavin, but just because they didn't give him anything to do. He's basically the first season Commander Riker on Star Trek. Yeah, he's supposed to be the young stud guy who gets all the women, just like Riker was supposed to be the dynamic guy and Picard sit in the captain's chair and manage things. But on Riverboat, Darren McGavin pretty much blows Burt out of the water, so to speak. He gets the women, he gets the action scenes (including the sword fight at the end of this episode). You can see why Burt Reynolds eventually left the show: he didn't have much to do. In this episode, Ben's got a romance of sorts early on with Joan, but he gets shoved into the background when Grey takes over.
The idea of a riverboat crossing open water is kind of interesting, even if the special effects look like the Hollywood Tour at Disney/MGM. (The one where they simulate a naval There's a few nods to continuity with a mention of other women that have messed Grey up. Although they can't keep their years straight. But overall, a good episode.