I remember Mt. Olympus very much.
I grew up in Myrtle Beach and often frequented Olympus. You remember correctly that it was located about 3 blocks off of the bypass in North Myrtle Beach. At the time there was a small amusement park on the corner which held a small woodie called "These United States". I never rode it as a youngster, but always stared at it as we drove past it to Mount Olympus.
Check it : http://www.rcdb.com/ig2532.htm?picture=1
Anyway, on to M.O. As I recall it, there were only 3 slides from the top of the mountain. They varied from beginner, to intermediate to advanced. I do remember that a lesser slide broke into the advanced slide halfway down the mountain. I never really picked up on how they kept people from colliding with sliders from above, but I never remember a problem occuring. All the slides came together into one pool at the bottom. There may have been a tiny slide for the kiddies, but I don't recall.
My aunt and uncle have a huge house a few blocks from that and my dad's side of the family gather for Christmas there. We drive right down that road every year and I look at the lot which is razed completely to the ground and is flat as a pancake. Ahh, memories... like the corners of my mind.
Hope that helped. 8)