With the level of ability you discribed . I reckon Lake Cootharabah would be a winner for you and your family. Shallow vast expanse of water great for beginners.If you get in trouble you can walk home But beware Easter can be busy and it usualy rains and blows like hell!!

Robes classic, bit more than 4 hours though

I'll be staying at Burrum for easter for the Fishing Classic.
I will be taking sailing gear of course.

Increased boat traffic and people fishing off the speed strip may be an issue.
I'm banking on the theory that the wind will drive the fisherman away so the two activities shouldn't interfere so much with each other.

PM me if you want more info about Burrum or to hook up for a sail.