B6Bliss --
Are you sitting on Bainbridge, sipping hot toddy (or some other alcoholic concoction) looking at a map of the US???
Being from Seattle, but having lived in several cities that you mentioned as possible bus routes, I assure that many of those are NOT feasible at all.
For example, IAH-SAT would be a 4-5 hour bus ride (if the bus obeyed traffic laws). That would simply be unacceptable.
CLE-CMH is a 3 hour bus ride -- again too long!