First time in Oman - What to see?

Hi,

I arrived in Muscat from Doha yesterday, only for Eid holidays leaving on Wednesday. I was suppose to be with a friend but didn't make it so I'm left all alone to explore this city.

What are the best things to see in Muscat? My interests are beaches, mountains, wadis. shisha and coffee shops. I heard about wadi but they say it's quite far, my rented car can only run up to 200 KMS a day, going to wadi might be too far for me. Is there any other place to see that's similar to those? Or is there like a group or tour that does this?

I'd be glad if anyone here would be willing to help. Please inbox me.

Thanks!