A very nice trip starts with slow moving water, building into g2, then entering a couple of g3 gorges which get g4 at high levels.
Best to take a 4WD to reach the get in, there seems to be quite a hole in the road in one spot.
Get out at lemonthyme power station.
1.5-2m is a good level, you can go down as low as 1.1 from memory?, but remember that it will take you longer.