You probably know this, but If you use the Thruway Motorcoaches, they guarantee connections with Amtrak. I've taken the BFD - LVS Thruway Motorcoach before - transferring from/to a San Joaquin at BFD. Though not the train, it was not crowded, so one could spread out across two seats and enjoy watching the scenery roll by. Overall, it was a pleasant experience.
On the other hand I've taken some long distance bus trips that have made me really wish I was almost anywhere but on that particular bus. The seats seem pretty small if you have a large framed person next to you. It can get rather claustrophobic and very sleepless on an overnight run. Personally, I'll stick to rails for long distance ground transportation whenever possible and I've sworn off overnighters on the bus.