As I gather that forced busing at Amtrak’s sole and arbitrary discretion is a common and accepted occurrence within its culture, I was hoping the other members here could advise me on the likelihood of receiving a full refund and cancellation of my LSL journey should I decide that travel on Amtrak trains—or buses or cars or donkey carts—is not for me.
You should be able to get a full refund for cancelling if you talk to an agent and (politely) explain your reason. Don't do it online via the website.
Bear in mind, though, that if your trip extends beyond Albany, the only practical way to retain your roomette on the rest of your journey would be to accept the bustitution and partial refund.
As to your dreams, Boston to Albany is not overnight, meal service (lunch) on the train would have been from the cafe car, with a selection that strongly resembles a 7-11 convienence store (packaged sandwiches, zapped burgers). Dinner service would be provided beyond Albany on the train if you are traveling that far and retain your reservation. It could be something vaguely resembling your fantasy, the dining car comes up on the New York section that's attached at Albany. Though YMMV on the "smiling" part, Amtrak onboard service is notoriously inconsistent, and the food on the Lake Shore diner is still the infamous reheated "Flex" dining service.
For what it's worth, cancelling and bustituting Boston-Albany wasn't at Amtrak's "sole and arbitrary discretion". It wasn't Amtrak's call. Amtrak is at the mercy of the host railroad, in this case CSX. If CSX closes the line because they want to do a maintenance blitz, which is the reason, Amtrak cannot run the train. Amtrak's only exercise of its "discretion" was to decide to charter buses rather than to "cancel without alternative transportation".
Finally, your vision of your trip is pretty much a fantasy, even if not bustituted. New York Central's
New England States would probably have fulfilled it, but you missed it by several decades. Amtrak won't come close. I often compare traveling by Amtrak sleeper travel to a cross between Motel 6 and camping, with meals at Denny's. Based on your stated expectations, you should probably should just go for the refund and forget Amtrak for future sleeper travel. You will inevitably be expensively disappointed. I, for one, tolerate Amtrak's innumerable deficiencies because it is the only game in town for long distance sleeper rail travel. If there were a rail travel alternative, I would take it. I do not think I am alone in that here.
Take the money and run.