I have recently visited the place and most locos and rolling stock is intact (although some dick heads have gone through the place with a can of spray paint), About 2 years ago there was a scare that that new "Huntlee" would knock down the place and put some snobs houses on there and that many carriages would be scrapped this will not happen to my understanding, all locos except 4627 are in great condition and most are undercover I'd say about 70% of the carriages are under cover as well, R766 is almost done and will have it's boiler checked for leaks very soon. The 10 classes are still there as are 'old mate' Keith can't move them until he builds a shed or something and the 49 44 and 47's are operational to my knowledge. I can answer some questions you may have. i anyone has some more info please post it here. Contacting them may be a bit tricky there landline does not work and the only way to get a hold of them if with the mobile number.
This video I put together has most of my pictures.
https://www.youtube.com/watch?v=180pQBArUR4
And their website
http://huntervalleyrailway.tripod.com/