We've been to Hamilton a couple times. The first time we stayed at the Reef View (before the last renovation) and the second time we rented a private apartment.
The apartment was by far the cheaper and best option. We had a cart included in our rate, two bedrooms, fully equipped kitchen and a pool in the complex. Plus access to all the resort pools.
Food on Hamo in the restaurants is expensive,, so we ordered Coles online to be delivered on our second day and made breaky, snacks and lunch in the apartment, then only ate out at night.
We stayed in this block on the ground floor, so the kids could walk straight out onto a huge expanse of lawn and kick a footy or run around. Guy met us at the airport to transport us with luggage and drove us back on the last day. http://www.stayz.com.au/51795?&numNigh...=3&rating=0
Most day trips to the reef are full days out, so if you have toddlers it may be too much. Even our 7yo was restless and a bit bored by the end as he isn't a great swimmer.