Yes we stayed at the Mullumbimby ground a year or so ago.

It is very very basic.  The loos are a fair way across the footy field so leave plenty of time to get there.

We camped right on the river bank and had all our own amenities on board so it wasn't too bad for us.

I think for what they charge and what they are offering, well, let's just say  don't expect luxuries.

You certainly can kayak from the banks of the river here and there is, or was at least, good fishing.

You would have to check if they are pet friendly as this option wasn't one of our things.