I would have shut the Exe Valley line north of Tiverton, done some minor work to upgrade line speeds to say 60 where possible, and then extended the Bristol-Taunton trains down it to Exeter. Used to double up the buses to Exeter in the mornings after the line was closed until everyone got cars & finding a parking place in Exeter became a combat sport. Jct station was a rather under-used, wistful, sad and smelly ( thanks to being build next to an abbatoir ) place befoire closure, and I generally found myself almost alone on the bus by the time it reached Parkway...
"Useful diversionary route!" ahem. Well, it was very occasionally