If you are walking in the Grampians, the obvious choice for a long day walk is the Major Mitchell plateau and the track that runs from Jimmy Creek to the gated road on Mount William. I had this on my tick list of walks to do while at the Grampians, but was not expecting too much of the walk as the ridge does not have the interesting rock features of some of the other areas of the Grampians, and, I suspected the trees would be too thick to prevent views.
Turns out I was wrong and this long walk (19 km, 1500 metres of gain from Jimmy Creek) was one of the best walks we did in the Grampians. Apparently, Victoria Parks considers this a "remote" area so you have to register out to do the walk and back in again when you finish. This is easily accomplished at the Visitor Centre, but, when questioned by the Parks staff, I glossed over the fact that I would be walking solo from one end, and my partner solo from the other. All these bureaucratic bodies get unduly concerned about people walking alone or doing other things they consider foolhardy.
If you had someone to drop you off and pick you up, the logical way to do this hike is from Mount William down to Jimmy Creek as the track is overall down-hill. Without that luxury, one of us had to endure a lot of elevation gain, and the other had to endure a lot of elevation loss. Personally, I - and my knees - would rather walk up than down but I gave Doug, who has a slightly bung knee after an adventure in Umbrawarra Gorge, the choice. Secretly, I was glad that he opted to start from Mount William leaving me to start from Jimmy Creek.
The track climbs steadily from Jimmy Creek until it reaches a big gently inclined plateau where the various Wannon Creeks drain to the west. There's not much point giving a step by step breakdown of the hike as there is really only one track, and you simply follow it, mostly up, but occasionally down. At about five kilometres (roughly 1.5 hours) you reach a cleared helipad and the track joins a rough road for a short section. You can escape off to the south here down to Mafeking. Shortly after this junction, you encounter the steepest climb of the walk where the track gains about 200 metres in half a kilometre. There's also a bit of rocky scrambling here.
The next five kilometres along to Wannon Campsite is wonderful walking along the ridge top with expansive views in all directions, but, most prominent the jagged Serra Range to the west. The bush is low scrub reminiscent of the heathland bush found along much of Australia's east coast and flat slabs of rock provide easy walking. There were masses of different coloured wildflowers blooming when we did this walk in late November. I met Doug somewhere around point 1152 metres about 45 minutes from Wannon Campsite.
I stopped for lunch at Wannon Campsite where there are clear tent pads, an outhouse and water from Wannon Creek. A short climb out of Wannon Campsite leads to the steepest descent on the track down into Boundary Gap. This is a scrambly section of track that eases as you descend but you'll lose about 170 metres of elevation in just 300 metres. It feels like a long climb out of Boundary Gap - it's about 250 metres - and, once up the first climb, the towers on Mount William look very close. But, there are still two or three more short descents followed by slightly longer climbs until you finally reach the paved road at Mount William. Turns out that Mount William (1167 metres), or perhaps point 1167 metres south of Wannon Creek, is the high point in the Grampians, so you can feel good about completing a long walk and tagging the highest point in the Grampians.
Apart from Doug, I didn't meet anyone until I was almost back down at the gate on the Mount William Road and that gives this walk a wonderful remote feel. If you don't mind humping an overnight pack, there are definitely worse places to spend the night than Wannon Campsite.