I did not notice of any public transportation to St. Lucia, there might be some but anyhow, it seems everyone come with his own car or boat to this place.
There is very little information on how to get to St. Lucia from Durban. This is what you can do.
Take the 9am Greyhound bus to Richards Bay from the main bus station in Durban. The bus will take about 2.5 hours and cost R140.
The bus will drop you off at a McDonalds. You must walk about 1 km across town to the mini bus terminal. Ask around where the mini taxi leaves for Mtubatuba (1hour) R15. From Mtubatuba you must grab yet another mini taxi to St. Lucia village (45 min) R10.
It sound hecktic and it is a bit, but it is cheaper and more adventurous than the Baz Bus.
It is difficult to get around St. Lucia's many nice game reserves. If you want to visit Cape Vidal or Mkuze, Hluhluwe-Imfolozi renting a car is your best bet.
It is possible to hire a car from Imperial Car Rental in St. Lucia. When I was there over the summer they had a weekend rate that was really good. You can rent a Tazz 1.3 for R153 a day with 100 km per day free. The mileage isn’t much and you have to watch it, but the weekday rate is a ridiculous R295 per day. We hired the car Friday afternoon and returned it Monday night and still got the weekend rate. If you really want to see the great parks in KZN you must have transportation and renting is much cheaper than taking a tour, especially if you have at least two people to break up the cost. Location: St. Lucia Village, on Mckenzie Street behind the petrol station.