Interesting comment about man-made trails being do-able and rambler-free... I rode the black route at Dalby forest a few weeks ago and it was neither - I doubt anyone would be able to ride it all - slimy switchback climbs, track littered with branches, one horribly eroded gully that might go and then on the best descent I came round a corner and nearly piled into a family - kids, dogs, picnic basket, the works...
I think Coedy is an excellent place but am less convinced by Dalby - why build an MTBing centre right in the middle of an area with excellent trails anyway?