Hi Paul!
Constantia is a very safe place, you can even walk but there are no boardwalks and no nights at night.
There are some great restuarants arround, but do a reservation. It is impossible to get a place in the good ones like Buitenverwachting or Constantia Uitsig spontaneous. Steenberg Restaurant is great and try the Warthog Curry in 'Zansibar' next to the Constantia Shopping Mall.
There is a Game Farm between Swellendam and Mossel Bay, where you can see the Big Five. I haven´t been there, here is the web page:
http://www.grgamelodge.co.za/
Greetings from Cologne /Germany