From the start point on Yarra Road (at waypoint ‘START’) head gently upslope WNW through open wandoo woodlands. Cross an old vehicle track at ‘1’ and then skirt around the edge of a dryandra ‘Parrot Bush’ thicket (near the crest of a ridge at ‘2’. Follow the route from ‘2’ to ‘5’ along the gravelly NW flank of a laterite-covered ridge, still mainly in open wandoo woodlands, but crossing a heath-covered ridge spur at ‘3’ and a stream gully 250m past ‘4’. At ‘6’, veer westward from the generally WSW heading to cross the gentle valley floor and then further veer to NNW at ‘6’ and then follow a gentle valley, crossing the stream bed at about ‘8’. Then ascend slightly along the western valley flank to reach the ‘8-1’ where there is an area of laterite boulders among pleasant wandoo woodland and zamia palms. This is a pleasant rest point before crossing a stream gully to ‘9’ and then ascending more steeply across more rocky, mainly heath-covered ground via ‘9-1′ (with views NE to Mount Yetar ridge). Reach a ridge at ‘9-2’ and ascend a small laterite-capped hill at ’10’. The route then descends NNW along the ridge to reach a granite outcrop at ‘11’ with some views across the Helena River valley. Veer sharp right to continue downhill, NE-ward through sheoak forest and across rocky ground via ’11-2’ to meet Ridley Road (dirt road) at ‘12’. Turn right to follow Ridley Road eastward for less than 100m to the junction with a vehicle track on the left. Turn left to follow the track (deeply rutted by 4WDs and trail bikes) downslope to reach the Helena River at ’12-2’. (Or see Option 1 below to shorten the walk a little.) Cross the River at a ford above a small waterfall and narrow pool. Heavy use by 4WDs and trail bikes has degraded this otherwise picturesque place, but it remains a nice spot for a rest. Return to Ridley Road by re-crossing the River at ’12-3’ (or at the original ’12-2’ crossing if it is flowing strongly), and following vehicle tracks southward from ’12-4’. Cross Ridley Road to ‘13’ (just past a stream gully) then veer right to climbs a fairly steep and partly rocky spur ridge ~SE-ward via ’13-1’ toward Mount Yetar. After ’13-1’ stay off the rocky crest of the ridge, slightly downslope on the SW flank. Cross a small granite outcrop at ’13-2′ and ascend another small outcrop at ’13-3’. Then veer slightly eastward to re-cross the crest of the ridge to a larger, northward sloping outcrop at ’13-4’ from where there are good views across the valley. Climb to the top of the outcrop and through a short section of scratchy heathland before again reaching open wandoo woodlands at about ’14’ on the laterite-capped northern slopes of Mount Yetar summit ridge. Head southward onto the ridge via ‘15’ gaining pleasant views to the west down Helena River valley toward Mount Gorrie area. Follow the ridge SE-ward via ’15-1’. Veer slightly right (SSE) at ’15-2’ to bypass the unremarkable, low heath-covered actual Mount Yetar summit area (at ‘SUMMIT’; elevation 353m). Cross a small laterite-capped hill-top on a southern spur ridge then veer ESE to cross the head of a small gully after ‘17’. Reach a smaller spur ridge at ‘17-1’ in oipen wandoo woodland, close to a small, steep-sided laterite-capped ‘knob’ (or butte) at ‘18’. After climbing (or bypassing) the knob head northward steeply upslope back onto the main ridge to cross a similar but larger and higher laterite-capped knob at ‘19’. This knob is a beautiful place for lunch and a rest (either on the top, or on the SE flank), with some views through the wandoo trees across the surrounding woodlands. Continue NE to NNE along the ridge via ’19-1’ (ignoring the rutted tracks caused by increased illegal trail bike activity in recent years; see Alerts / Issues). At ’19-2′ cross the crest of the ridge and descend slightly to reach the upper slope of a bare rocky outcrop area at ’20’ from where there is an expansive eastward view across the Mount Billy area and beyond. Climb back NW-ward to the ridge to a high point in wandoo woodland at ’20-1’, which is almost at the same elevation as the true summit to the SW along the ridge, bypassed earlier. Continue NNE along the ridge via ’20-1’ then at ‘21’ veer right (eastward) and head down to eastern flank via ‘22’ and ’22-1’. At ‘23’ via sharp right (southward) and continue to descend. Cross a gully at ‘23-1’. Veer left after crossing another small gully at ‘24’. Cross another stream course at ‘25’, then veer left (ENE). Climb to a broad ridge to cross Yarra Road at ‘26’. Head eastward and cross a gentle hill top at ’26-1’ on a small spur ridge. At ’27’ veer ESE to continue upslope. At ‘28’ just before reaching a narrow N-S ridge crest, veer southward to follow the western flank of the ridge gently upslope via ’28-1’. At ‘29’ veer left (SSE) onto the crest of the ridge and continue through a sheoak thicket via ’29-2’. Divert to the top of small NE-sloping outcrop on the NE flank of the ridge at ‘30’ from where there is a god view across Helena River valley to Mount Gorrie (elevation 299m) and Mount Clifford (elevation 349m). Return to the ridge at ’30-1’ and continue upslope via ’30-2’. At ‘31’ near the foot of the laterite-capped hill-top just to the south (elevation 341m), veer right (WSW) and cross the steep gravelly slope at the head of a westward plunging gully. At ‘32’ veer right to head more directly WNW down the hillside via ‘32-1’. The slope soon becomes gentler and an old vehicle track appears which you can partly follow to return to the start point on Yarra Road.
Option 1, to bypass the visit to Helena River (from ’12-1’): Instead of turning left to the River at ’12-1’, simply continue on Ridley Road for a further 100m to continue the described route from ‘13’. This short-cut reduces the total walk distance by less than 0.5km.