I never recalled seeing him in anything after Green Acres,, though after posting it I checked the iMDB, and saw that he had a moderate career, appearing in several series, including Marcus Welby MD, Little House on the Prairie, and even the soap opera, Santa Barbara (a show of which my inveterate.friend, the oft-mentioned Chris Dunn could spin a tale or two, having written for it) Tom Lester also was in a couple of tiny movies, though his most notable film was Benji. There was about a 10-year period with nothing, starting in the mid-90s, and then surprisingly a few things started to crop up. (I wonder if this coincided with reruns of Green Acres getting shown on Nickelodeon or wherever it was aired.) And then, to my shock it turns out that only last year he shared the lead in a feature film!
From all I can tell, it's a very low-budget affair, Campin' Buddies, about a couple of deeply, dim-witted old friends who go camping, very poorly. His co-star is singer Ray Stevens, best known for his novelty songs like "Ahab the Arab" and "The Streak," but also a big mainstream hit, "Everything is Beautiful." The cast also features Don Most from Happy Days and Victoria Jackson from SNL.
Here's the trailer for Campin' Buddies.