I lived in Boston for 2 years just before the big 3 came to fruition, when the team was bad but everyone in the Boston media loved Rivers. Ryan, McMillan, Holley, WEEI, all of them. Except Simmons, who was still living in LA. Simmons wrote column after column criticizing Doc, and in between those columns he'd go after him in mailbags. Bill was a little obsessive, but to be fair, Rivers was terrible. He did an awful job managing rotations, his in-game adjustments were poor, and defensively the Celtics were brutal. Remember, this is before Ubuntu, Thibs arriving, and KG/Ray showing up.
That said, Simmons doesn't strike as the kinda guy who would write letters or try to sit down with owners. He's passionate, but he's not insane. One, he has admitted in the past that he writes better (and more popular) columns when his teams suck (ie. the Red Sox pre-'04). Two, he lives on the West Coast. Bill's going to travel across the country to meet with owners?