Use everything in your arsenal to keep safe.
If you have a Sat Nav they can certainly give you an idea of the sharpness of a bend, but as someone else said the vanishing point will tell you when to start applying some power coming out of a bend, but remember bends sometimes have a double apex and can tighten up again and the vanishing point will not tell you about the broken down coach just out of sight as you start to apply the beans.
Common sense and self preservation will stand you in good stead, as will sensible use of a Sat Nav and using the V Point. Local knowledge is also useful for everyday riding, but statistics show most accidents happen with 3 or 4 miles of home.
Watching for telegraph poles along county roads can give you an idea of the direction of bends in the road ahead (they tend to follow the road, but not always)
Fresh clumps of dirt/mud and grass along a road could indicate a tractor could have recently passed that way or is around the corner cutting the hedges, a pile of manure in the road could mean horses or cattle in the road around the bend.
Keep your wits about you and don't be lulled into a false sense of security.
When riding with mates things can sometimes get out of hand, everyone one wants to be a Mr Martin, if you start to feel it is getting silly drop back, better be 5 minutes late than dead on time.
If you do go around a bend to quickly and are surprised by a obstacle in your way, start your braking/avoidance procedure and look away (Avert your gaze) from the obstacle and manoeuvre the bike around it or stop, Target Fixation through surprise or fear will steal you no claims bonus or you life quicker than pretty much anything else on a bike.
Stay safe, ride with dipped headlights on, wear bright colours, I know a floro waistcoat and a floro yellow skid lid does not look cool, but then neither does a foccing wheelchair.