Was in Gero last year around early October and hit a week of really great weather... ...for bloody fishermen!

The day before and the morning we left were 30K so I watched the graph and noted only three more days of wind, four without etc. Can be a bit fickle at that time of year.
Cheap shacks at Point Moore in the Quokka for about $50 per day. Coronations north of Gero may be good if you are self sufficient camper. Shops about 15-20km away, so not too bad...
Take a weed fin for Denham. If the wind is up the ribbon type weed can get semi thick. Nice and shallow though! Or even Big Lagoon 3 km inland from town. Denham caravan park is good value put take a decent mallet to get your pegs in.
Maybe Gnaraloo Bay would be getting strong breezes about then? See if you can get in at fisherman's hut for a few days. Should be pretty slow that time of year up there.
Carnarvon rivermouth may be reliable too, though on high tides. Check the charts. Caravan park on the northern shore is 50-100m from launch site. Favoured by teabaggers due its shallowness.