Hi. I am planning to land at Heathrow in early June and have five days
to kill and instead of doing the usual in London, I was thinking of
taking a train to Devon, rent a car in Devon, staying for three or so
days and then heading out to spend a night on the Isles of Scilly. Then
drive back to Devon, and train back to into London, where we are meeting
friends.

Some questions:

1. Doable? Enjoyable? Looking for relaxing, quaint town, good food.

Sure. Well, I'd be inclined to skip the Scilly Isles as not interesting
enough to be worth the trouble of getting there.

Note that you have two main choices of where in Devon to switch between
train and car: there's Exeter, and there's Plymouth, which is on the
boundary with Cornwall.

Also note that trains are currently not running through to Plymouth:
one of the most scenic bits of the railway, where it runs right along
the seashore (at Dawlish), was washed out by a major storm last month
and the repairs aren't complete yet. They're expecting to have it back
in service in early April, though, so it should be fine when you go.
--
Mark Brader | "Opening a monitor case is not for the inexperienced
Toronto | or the faint of heart, unless you need
| defibrillation." -- Kevin D. Swan

My text in this article is in the public domain.