Have a wander round Exmoor -- lots of stone age forts and spectacular scenery; high sea cliffs etc etc
South coast along towards lyme regis is nice.
Could pop into eggesford for a cup of tea if they'll let you. If it's a warrior, don't come four up!
Fly out over to Lundy, but prob don't land if it's a PA28 and I doubt they'd want you to.
Bodmin is a nice enough shortish trip. Or Roserrow and have a cup of tea and a wander on the beach.
Bolt Head, longish stip and very near the sea etc. (www.devonstrut.co.uk
Circular tour of Dartmoor?
The world is your oyster, maxflyer.