The A1 road, called National Highway One, from Adelaide heads straight for Port Wakefield. It is around 100km by road.
Being a roadhouse stop on the road north from Adelaide, Port Wakefield has more than its fair share of coaches that will take you there. Yorke Peninsula Coaches (http://www.ypcoaches.com.au), Greyhound (http://www.greyhound.com.au), and Premier Stateliner (http://www.premierstateli...) together deliver around 10 services to Adelaide daily.
There is no rail or scheduled commercial air services to Port Wakefield. Adelaide is the best option.