You might ought to check the Coast shuttle. They were running to Bills but said they would soon stop since they don't own the property anymore. I think the Rio shuttle will take you to Harrahs on the Strip also.

As for the shuttle, I think it is $5 one way/per ticket. Unless you are local then it is a buck!

Valley of Fire and Red Rock are great choices!! And don't forget about Mt Charleston. It's getting hot here in Vegas!!