VegasTriker provided a good list of resources.
I have ridden to a number of locations and check my bike with the Valet Service. That has proven safe for years. I don't know if the hotel you are staying at provides that service.
The Regional Transportation Commission is trying to develop a bike friendly Las Vegas. They have a secure bike garage. You might check with them.
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They also have a list of bike routes that can be helpful. Let me know what kind of riding you are interested in.