Beyond Healesville in the Black Range State Forest is the Buxton mtb park.  Buxton is great fun and well worth the drive.  From the car park, follow the undulating tracks 1 and 2 around clockwise.  There are several creek crossings in the beginning before the climbing begins.  You'll encounter 2 inner trail loops, numbered 3 and 4, individually, they both start and end a short distance apart.  So you can take the inner track and then finish only meters away, and resume the outer loop.  Each is good fun and of intermediate difficulty.  Once you reach the top of the hill, the real fun begins.  The Spider Gully descent repeatedly transverses a gully, starting with tight turns and then opening up and the corners getting faster and wider as you descend.  The final descent section is a sculpted section of berms and jumps that has to be one of the most fun sections of track anywhere.  Beginners will be able to find a line that keep the wheels on the ground, while advanced riders can find plenty of air and high G corners.  There's about 20 km of trails.  The difficulty is intermediate.

Trail Map