We stayed at Rocky's and it really is a beautiful resort with great staff and facilities.
There is a restaurant nearby (about 5 mins walk - turn right out of the hotel), I cant remember the name but if begins with an S and did great seafood at a reasonable price, further along near the Grandmother and Grandfather rocks there are some small places that looked good as well. However in places there are is no pavement on the road which can be quite busy and I would worry about walking along it with small children.
You can get to Lamai (and back) really easily using the songtheaw which is very cheap and they seemed to pass the hotel regularly, we never had any issues getting one.
If you are hoping for a good beach for the children then Rocky's doesn't really have one, and what there is, is only accessible at low tide.
However there were plenty of children at the resort when we were there and they all seemed to be having a great time and the staff were very good with them.