We understand the situation. It may not be necessary for you to drive to California and obtain a smog check while the vehicle is being stored or driven in Nevada (specifically Las Vegas)., though if you'd like to, that will be perfectly fine as well.
You may pay your DMV registration renewal fees today, and the DMV will mail you your vehicle's new registration card and sticker (to DMV address on file) once the vehicle passes the smog check.
The other option... file a REG 5103 (Out of State Smog Check Exemption).
It's possible to do this directly through the DMV. Turn-around time is usually 30 days. Our recommendation would be to use www.NeedTags.com. You can email them the REG 5103 form and they'll do the rest. We'd recommend starting with sending them a support ticket online. Follow this link... NeedTags Customer Support.
From NeedTags How To File A REG 5103 - Quick Guide
Download: REG 5103