Rock Climbing is an upward movement puzzle. There are varying difficulties of routes to suit most abilities. Just remember you don't have be super strong, a little technique goes along way.
Abseiling is lowering yourself at a controlled speed on a rope from a height. It can be a great trust building and self confidence exercise taking in the views on the way down.
The ropes and equipment have high strength ratings and could hold a Rhino so no to need worry just take in the experience.