This comes from one of the later incarnations of the Bears' TV show. Like For Better or Worse, there have been many attempts to turn this Berenstain Bears into cartoons, with varying quality. There were some early specials, a saturday morning series in the 80s, and this newer series, distinguishable by the bluegrassy opening music, started in 2003
The Trick or Treat episode deals with the cubs wanting to stay away from Widder Jones, the local scary old lady in the scary old house on Crooked Lane. As if you couldn't guess strictly by the premise, she turns out to have the best candy in town. It doesn't get much less creative than "the woman thought to be a witch turns out to have the best candy in town" plot when it comes to Halloween specials.
The opening dialogue, in which Brother and Sister decide to go out trick or treating right after dark, could have been punched up a bit, but things improve from there. Pedestrian though it may be, this one has some fun getting around to the climax, as the cubs enjoy the sights of Bear Country around Halloween and talk about the rumors they've heard about Widder Jones.
It expands a bit on the book version of this particular story, if I remember that one correctly. It may not be all that creative as plots go, but it's still fun to watch, and at least Widder Jones really does get a kick out of scaring the crap out of kids with an awfully elaborate display before doling out the loot. As happens in so many of these things, the Halloweenish atmosphere saves the day. This could actually have stood to run longer than its 12 minute run-time.