Having said that, I'd suggest that it's not such a good idea unless you either have at fool proof way of getting back down safely (this probably means being able to see a least one area of the sky that is clear at all times), or you are capable of switching to IFR if needed
I have mixed feelings on this for non IR proficient pilots. I can remember a longer 200 nm flight I did in the early days of my PPL flying. Taking off with a well broken cloud above, climbing on top and then seeing those clouds close up enroute. They went to overcast and over the mountains the tops started rising forcing me to climb to nearly 9000 feet to stay on top and of course the higher you fly the nearer the freezing level you get even in summer months.
The other consideration is what is below those clouds? In my case high terrain so letting back down was a no no.
Your departure and destination may be fine but what about enroute?
Flying a twin from Northern Spain back to the UK both departure and arrival airports were CAVOK but all the airports enroute below the clouds were giving overcast 200 feet and 700 meters RVR! What do you do in a single flying VFR on top if the Donkey goes bang or you are forced to land for a multitude of other reasons?
its fools paradise sitting in the sun on top with God knows what below and no instrument capability
Pace