You didn't say how long your Vacationer is. Hwy 178 goes through Kern canyon following the Kern River. For about 20 miles going east, it is a very curvy two lane highway with some very close outcroppings of rock that can cause some damage if you get too close. Other than that, you shouldn't have a problem.
In all my years in this area, I've never stopped at the hot springs...
I would assume that if you're going to DV, that you would follow Hwy 178 through Ridgecrest and Trona. Hwy 178 designation ends before Trona (actually at the turn off to the Trona Pinnacles road) but continues on under the name of Trona Wildrose Rd. Anyway, the road over slate range also has some very sharp turns but easily done. Once in Panamint Valley, the road is not well maintained, but passable. Once this road connects to Hwy 190 (turn right at the stop sign) Hwy 190 then goes over Townes Pass with at 10% grade close to the top for a couple of miles. Once over the pass, the highway descends from about 7500 ft down to -200 ft in about 10 miles. Very easy to allow your speed to increase rapidly...
Hope this helps
Ron