Bearing in mind the days are still quite short in Feb, I think I would be planning to choose say three locations over 10 days and use them as a base to check out the local area, that way you can maximise the day and minimise the travelling in between. You don't say how you are travelling, but even if you have a car Devon & Cornwall is a bit ambitious for the time you have (understatement). many of the best areas are served by very narrow roads on which you can't travel too fast.

Assuming you want to walk/bus out each day my three places as bases would be St Ives, Looe and Porthleven. Only because I know them best, not necessarily because they are the best places. - These are all Cornwall - not spent much time in Devon.

You definitely shouldn't have too much trouble finding somewhere to stay. Besides B&B, lots of pubs have rooms - you sometimes take your chance with pub rooms, but I have rarely had a really bad experience, and most have been good-excellent. As its not high season, you should get better attention than when the hordes descend in summer.