The "thruway" buses already run. There are a couple of connectors between the Cap Corridor and Surfliner that run at off hours (when the Starlight isn't around), and there's a connection with thru ticket off the Cap Corridor in San Jose with a MST run to Salinas and Monterey (similar to the Santa Cruz connection, which is a thru ticket but the bus is the Hwy 17 Express). Since the MST runs aren't Cal-Amtrak operated, of course, the connection isn't guaranteed, though the bus and/or train will probably wait a little while if things are running only slightly late.