395 is a very beautiful drive and you'll mostly be going downhill. If you're comfortable with the braking of your truck on downhills. If you made it to Tahoe you should definitely by o.k. We wouldn't take it to San Bernardino though. We'd take 395 to Kramer Junction, CA then 58 east a short distance to Barstow, CA and I-40 over to 95 at Needles down to I-10 at Blythe then east on I-10 to Phoenix. Eliminating San Bernardino eliminates a lot of traffic.
Another option would be to go south on 395 a short distance to NV Hwy 208 around Topaz and to Yerington at Alt 95, then pick up Nevada Hwy 95 south to 93 at Kingman, AZ. It's a good highway. Fill your tank at the major towns and keep it topped off. Don't wait until it gets low.
From Kingman take I-40 east a short distance and pick up AZ 93 south toward Wickenburg, AZ then .... depending where you're heading in the Phoenix area there are options.
From Wickenburg you could take Hwy 74 east toward I-17/Cave Creek and depending where you're heading, take 101 over to the Mesa area or you would take Hwy 60 right into the Phoenix proper.
To bypass Phoenix entirely and continuing south toward Tucson you could continue from NV95 and stay on 95 in Arizona through Lake Havasu to Parker and on to Quartzsite. Then I-10 east to Buckeye and south on 85 before getting into the Phoenix area taking it to Gila Bend, AZ at I-8 then east on I-8 to Casa Grande and I-10 south.
Lots of choices!
Full-timed for 16 Years . . . Back in S&B Again
Traveled 8 yr in a 2004 Newmar Dutch Star 40' Diesel
& 8 yr in a 33' Travel Supreme 5th wheel