If you live in Muscat and ride motorcycles, you will eventually go to As Sifah. This map shows various possibilities, from the perspective of my residence in Madinat Al Sultan Qaboos (MQ) area.
1. From MQ, take the main highway toward Ruwi, (purple route) exit to Hamriya, then look for right turn to Yiti. Wind through narrow city streets, straight as possible to sudden uphill...the old Yiti Rd. Narrow, curvy, ups and downs...a blast. Follow signs to As Sifah for more of the same.
2. Alternatively, from MQ, take back expressway (blue route) toward Seeb, then Amerat exit. Wind up the switchbacks and over the mountains to Amerat. Follow signs to Quriyat. Take exit for Wadi Mayh and wadi route to Yiti. This is mostly a dirt road (yellow shaded on map) with a few dips and turns. It ends at the main road to Yiti. Take a right there to go to As Sifah.
3. Many other ways to/from, notably the Qurm Heights highway to the port of Muttrah (green route), and from there to Bustan palace area, and on to Qantab. At Qantab roundabout, take a right to get on track for Yiti and As Sifah.
All highly recommended on a quiet Friday morning. Just watch out for the goats on the road in Khairan!