In reply to olliehales:
No experience of cycling in Oman but I have done the trip from Muscat to Masirah (via Sur) by road, with lots of camping in amazing locations on the way. As others have said there are long sections of the trip where the scenery doesn't change much, but it is still stunning!
Camping is definitely the way to go, but there are also places to stay en route and I'd be surprised if you didn't at least find a small hotel or some locals willing to give you a floor to kip on in every place you found yourself.
As for the traffic being bad, as another poster said, I'm not sure where they meant but once out of Muscat there is hardly any traffic. Quriyat, Fins, Tiwi, Sur, Ras Al Hadd, Al Ashkarah are all good stopping points. Once South of Al Ashkarah there isn't much, from what I remember, but there are some great dune and spot to camp on the beach, right by the road.
Masirah itself is stunning in a desolate kind of way. We camped on a remote beach in the South of the Island and woke up to find nesting turtles by the tent. Very good memories if catching huge fish in the surf then grilling them over a fire with local fishermen.
Post edited at 10:16