San Francisco to HWY 95

Depends on when you want to go. Hwy 120 thru Yosemite to Hwy 395 may be closed sometimes until June if they get a lot of snow. I'd go i-5 south to Bakersfield and cut over from there instead.

120 is narrow and twisty but great views. I would take I-5 or 99 south to 58 at Bakersfield over to I-15 and into Vegas.

Your rig is big, but it will go over 120 just fine. It's steep in places and narrow in places but RV's and tour buses do it all the time. I have a 35' DP pulling a Dodge Dakota and I get over it just fine. And unlike the I-5 suggestions, it is a very nice drive. And none of the roads will be closed by snow in late summer. Other things may close them like fires and landslides, but not snow in the later summer.

Also once you get over the pass, I like taking 6 to 95 and coming into Vegas that way. 395 is a good drive too, but if you've done it a lot 6 and 95 is something different. You'll go through some middle of nowhere Nevada, but I love that kind of drive myself.

On Edit: I see the title of your thread is SF to 95 but I didn't see that in your post. So sounds like you are already planning this. I say yes, your rig will make it and it's a very fun drive. It would be a very looong drive to try and do it in a day, but two or more days and it's fine.