Shouldn't she be drawing a pension from SAG along with residuals given the amount of acting work she did?

Whether you get residuals or not depends on what type of contract you signed at the time of the movie or TV show. Some people make millions a year from old shows (e.g., Jerry Seinfeld) while others make only a few thousand dollars (e.g., Jason Alexander who played George on Seinfeld).

Difficult to say. She should be getting some kind of pension from her union, but how much would depend on how much she paid into it. Residuals would depend on how much she got paid for each project, and how much they get replayed. Besides The Shinning, what else has she done that people are still watch?

Residuals have changed a lot in last 20 years. Actors and their agents have gotten smarter about getting better long-term residual deals, thus ensuring more long-term financial stability for actors, even if their careers dry up. For example, the cast of Friends signed a great deal, and still make $20 million a year for a show that ended almost 20 years ago. Conversely, Seinfeld which ended only 5 years before does not pay very much to the main cast. Larry David and Jerry Seinfeld have each cleared over a billion dollars as the show creators.

Going back even further, according to George Takei, the original cast of Star Trek only got paid residuals for the first 10 replays of the show. That was done after two years.

She lived with a guy for 35 years. He must have been paying some bills.