This was the absolute best thing we did on our trip to Oman and UAE. Nizwa fort is amazing, and Jebel Shams was absolutely dizzying and breathtaking. Our guide, Khalid, was extremely kind, courteous, and pleasant over the long 11 hour trip, and we loved getting to know him. He was especially helpful in the Nizwa Souq, where he gave us a tour of various dates, spices, halva, saffron, honey, and more. Unlike other souqs we visited, the merchants were helpful and patient rather than pushy.
If you're in Muscat, you have to get out of the city to see more of this beautiful country.