Central Coast. Where to go or not to go?

Were going from long term renting on the Northern beaches to trying to buy on the Central coast. We have 3 kids, 1 in high school 2 in primary and have a modest $700k to get a 3 bedroom place. We dont want to go any further North than Norah head as we still need to get to Sydney a couple of times a week. Would appreciate any recommendations on suburbs to look at that are safe with good schools close by and places to definitely avoid. Were thinking of Killarney Vale, woy woy or Niagara park so far. Thanks