There is nothing new about propane or compressed natural gas powered buses or delivery trucks, our family food distribution business ran CNG fueled delivery trucks back in the 1970's during the oil crisis. It was a headache then, and it is probably a headache now, though is an option for local area delivery if one has their own CNG fueling station.
As to RV's I think we will see full self driving show up making what we have now obsolete before we see a practical electric motorhome. I also don't think we will see it in the next 15 years, probably not in the next 20, there are just too many infrastructure issues to overcome, not to mention battery technology issues, though those are getting better all the time. Perhaps we will see a national grid of charging stations for larger trucks along the interstate highway system in 10 years, but that does not help the RV owner that wants to travel the back highways.