If you can't get out with a 180 turn, put the plane down before you are in cloud. Climbing without a good, preplanned, gps track, will have a high risk of hitting something in hilly country.
Why fly a single engine over cloud covered mountains? You're safer following the valleys, provided you keep a few hundred feet below any cloud you see, as well as a few hundred feet above the terrain, and for your legal visibility take the distance at which you can see a low cloud against a grey background, not a white house on dark moorland.