Ok, After a couple of phone calls my thoughts are:
Location: Pemberton. Has a Caravan Park, B&B's, Homestays, Farmstays etc nearby, Good Hotel with good food.
Great roads for riding close by and lots of things to do and see nearby as well.
Date: Has to be moved as it is the beginning of the school holidays,
my thought is bring it froward one week to the 1st and 2nd of April. After the school holidays there is too much chance it will be very cold and wet
Nearest Airport is Perth: not that far for a pillion to make the ride on the back