If there is a service disruption is being bussed the only option?
Am I right in thinking that it depends where you are when the disruption happens? (and if there is space available)
For example, if you were holding seats on 20 from NOL-WAS, do they at least offer the possibility to take the CONO to CHI and then on to WAS, or is the only possibility to go Greyhound?
I do not know the answer to your question, but note you refer to Greyhound. All this talk about buses does not necessarily mean Greyhound, either regularly scheduled or spare bus equipment.
When I encountered a bustitution recently, between Anniston, Ala and Atlanta, it was not a Greyhound at all. It was a bus which belonged to some kind of singing group. They brought it to the train station in Anniston and it took us straight to the train station in Atlanta, I-20 all the way.