This has been on my list to do - an overnight stay at Rocks Hut in the Richmond Forest Park. 

The trip involved riding up to Coppermine Saddle (stashing the bikes in the bush) followed by a 1.5 hr walk into the hut over Dun Saddle.  The weather delivered supreme crisp clear days and staying at Rocks Hut added another dimension to the Dun Mountain Trail made all the better by riding from home via the Nelson cycleway network.