I cringe when people talk about Maldon. It's soooo passé. Maldon has been tarted up just for the tourist dollar, and for many who come from the district, it is not for the better of a town that has been stripped of its soul and character at the alter of commercialism. Shops are owned by people living in Melbourne, opening on a whim. My roots are in Newstead and Castlemaine (16km respectively from Maldon) and the whole family remembers when Maldon did have character and its ambiencce. Not anymore. For originality, look at Muckleford and Newstead, Strangways or the old Swiss-Italian settlement of Yandoit with its many ruins. Yandoit is as far off the beaten track as you can get, and the further you go the more you uncover.
The campground at Tarrengower on the outskirts of Maldon town is OK, but you can also camp wild at Mount Mournpal to the north of the town amidst a jumble of granite boulders.
I second the Valley of a Thousand Hills as a very good suggestion with surprising light, though I'd angle toward a pub overnight (Flowerdale, Yarck) rather than camping — May is cold and dark.