These are the options I've discovered so far:
1) Asla bus company: takes either 5hr15m or 5hr45m, depending on departure times offers more departure times; prices same as train or a bit more for faster option.
2) Alvia, Renfe's high speed trains take equally as long as the buses
3) BlaBlaCar, one hour shorter than bus and train; Spain's ride share analgo to Uber: but much cheaper; ride option availability only becomes available a few days prior to departure. This is a long time to be driving with someone unfamiliar...which could be a positive and/or a negative.
I'd appreciate any insight/advice, thanks.