Beloved of Sir John Betjeman, and who would dream of questioning his judgment (at least in this respect), Cornwall is always quieter, and easier to get to than I expect. Yes, getting back round Exeter on a summer Saturday can be a drag — but that's coming home.
Actually, this is a very depressed area, now that the tin mining is near enough dead and most the tourists have gone to hotter climes. Yes places like St Ives and Newquay get packed, but elsewhere, you can usually get a seat in a pub, if you don't leave it too late, and the traffic flows steadily, if not speedily.
Good pubs, great beer (St Austell and Sharpe's Breweries), plenty of seafood, sun (usually), beaches, lots to see and do, what more could anyone ask for?