Just so happens that I drove that the other day. F350 and 34' 5ver. If you drive across 58 from Bakersfield to Barstow you'll be on all good 4 lane highway. The pull up from Bakersfield to Tehechapi is pretty steep but definitely doable. Our clutch fan was wound up all the way from about half way up to the top. It's a 15 mile pull.
Once you get into AZ there are a couple of fairly good tows on I40, but at 6% or less none are major league.
Be sure to fill up at Barstow and not around Needles - then, once you get into AZ prices drop considerably.