I can't add anymore regarding Cornwall for golf, beyond what everyone else has said, in that St. Enodoc is a must! If you are going to stop off for golf on your way down then out of Burnham & Berrow, Saunton and Westward Ho! aka Royal North Devon, then it will depend what you are after.
Easy access just off the M5 and a great links experience then Burnham is your course. If you want 36 holes of good solid and fair links that many will say could (almost?) host the Open then Saunton is your best bet. If you want to step back in time for something a little bit different then its Westward Ho! you want. Both Saunton and Westward Ho! aren't the easiest to stop off at on your way down, but I would say that the experience at Westward Ho! is worth it, ignoring some of the flatter holes the drive on the 4th over the railway sleepered bunkers and some of the middle holes in the dunes are well worth the drive, and its a great old fashioned clubhouse. And don't forget, its one of a certain Mr Tom Doak's Gourmet Choice courses but as he says, its not for everyone!
As far as somewhere to stay is concerned, I've never really done Cornwall as a golfing holiday, but I have stayed at The Old Quay House in Fowey on the southern Cornish coast, great little hotel and nice restaurant:
http://www.theoldquayhouse.com/Not much golf in the area, but perhaps a nice stop if you want a break from the golf and fancy going to the Eden project which has to be seen to be believed.
Hope that helps?
Cheers,
James
ps I'm only a country member at Burnham so I don't live locally but if you fancy it, let me know and it may the excuse I need for another trip that way...