I don't think I would recommend it.
Hwy 190 climbs from -100 ft to almost 5000 ft in a long curvy road leading to the summit of Towne's Pass. From the summit there is a 10% downgrade for about 5 miles (maybe a little more) down to the Panamint Valley floor...then once again climb up over the Cerro Gordo mts on a VERY curvy and 6+ grade before getting over to Owens Valley and Lone Pine.
Your motor home better be in tip top condition, and I'm sure it's temperature will climb sufficiently that you'll have to pull over to let it cool off.
You can by-pass this last climb (out of Panamint Springs) by taking the cut off (in the Panamint Valley floor - before you get to Panamint Springs) over to Trona and Ridgecrest to Hwy 395. There is a small climb over Slate Range just before dropping into Searles Valley and Trona. This grade is at least 6%, but it's only a couple of miles long and does have a couple of horseshoe turns.
Note my location...I'm only a few miles from there and have lived here most of my life...so I know this area quite well.
During May, I would recommend going the Trona way or as far as Stovepipe Wells, and then back track over to Furnace Creek and then go out of the park via Death Valley Junction and Baker to I-15. From there you can go west on I-15 to Barstow, Hwy 58 west to Hwy 395.
Good luck and I hope this helps..
Ron