Something I'm not clear on. Is the Story of King Arthur and Camelot just myth or is it based on some historical fact?

It is Historical Fact.
Some of the tales surrounding this are myths, but the rest is Fact.
I know, as I was working once on my Family History through Ancestry.com, I found a Direct Family Link to King Arthur and Guenivere.

Yes, I agree that King Arthur was a very real man, but during the Middle Ages, his story became romanticised and that's the story that's stuck around.

Supposedly, when over in England, I visted Gladstonbury and saw 2 graves, that long ago monks discovered, held/hold the remains of Arthur and Guinevere and are buried on the grounds of the abbey, south of the "Lady Chapel", between two pillars. Not that much of an inpressive sight but still interesting enough to ponder how much is reality and how much is myth?