we do Maui in the spring. every year for past ten years. right after the whale-watchers leave. rent a condo near the city beach. rent a car. little island but lots to explore. make sure you drive to Hana yourself if you have the guts. more opportunity for stopping than if on the tour bus.
if you wait til summer, more tourists, more kids, higher prices for everything. bring your Costco card

it is but you need to go off season for cheaper rates; and search for reduced timeshare rentals (cheaper then hotels);people typically go during the summer months and not realize it does stay pretty warm all year long