The express train from Noarlunga station to the city used to take less than 30 minutes.
I drove from Morphett vale into the city for months and with the expressway working it took between 28 and 40 minutes depending upon rush hour or not.
My opinion (not advice) is to live near the beach. look out on stunning views. Walk on the prom. Get away from the hussle and bustle and only subject yourself to that when you have to.