It's a great journey, but slow once past Exeter (although very scenic in parts). Biden is apparantly a bit of a rail geek ("Amtrak Joe") so might appreciate Dawlish, the "Devon banks" (some of the steepest mainline railway in the UK) and Brunel's bridge across the Tamar just after Plymouth. The branch line from St Erth to St Ives must be the prettiest in the UK - and is currently having it's track renewed (which Network Rail are saying is a coincidence of timing!)