I saw this movie in a theater when it came out in 1986, and was pretty charmed by it at the time. For some reason, it's unavailable through normal streaming services, but YouTube claims that it has the full movie. I went for the Blu-ray, which was on sale at Amazon. Alan Alda deserves whatever royalties he can get, I figure. He wrote, directed, and stars.
Mr. Alda plays Michael Burgess, a history professor in the small college town of Sayeville. He's written a book about a Revolutionary War episode that featured a battle and a plucky patriot heroine. Hollywood bought the book, and (as the movie opens) the movie company descends on Sayeville to shoot on location.
A lot of stuff goes on: Michael is enraptured by the actress playing the historical heroine, and who can blame him, it's Michelle Pfeiffer. This threatens his already-rocky relationship with girlfriend Gretchen (Lise Hilboldt). He gets horrified by the ahistorical liberties taken with his book by the scriptwriter (Bob Hoskins) and the brash director (Saul Rubinek). And Michael's dotty mother (Lillian Gish!) is developing health issues. The actor playing a British general (Michael Caine) is an impulsive loose cannon, with designs on anyone wearing a skirt, including Gretchen.
It's complicated, but moves along with its own screwball logic.
Both Lillian Gish and Michael Caine absolutely steal every scene in which they appear.
And, hey, that's John C. McGinley, in what IMDB claims to be his first movie role. Not to be his last.