We drove past Mt Barker on the Freeway today, and it takes about 30 minutes of easy driving to get into the city. You would probably have to travel along the freeway and then head down to the beach at Brighton or somewhere on the South Coast. One can travel along the country roads and come out through Happy Valley but this would probably take longer. I guess that it would probably take a 1/2 hour or so to the nearest beach, but would warn that Australians only tend to go to the Beach in the evenings when the Sun is going down, as often if it is a day like today 35degrees, the sand is too hot to go on. We were down in Victor Harbour, Goolwa & Port Elliot yesterday looking at housing. There is lots around and a new 3bed detached house on a Marina with your own landing stage was for sale at A$300,000+. This area is about 1 hour from Adelaide and a generally bit cooler, but the road to the city is quite narrow and winding.