For most RV Use cases, they should be the last vehicles electrified.
If you look for used RVs, the thing that strikes you is how few miles that they have on them. A 30-40 year old RV will normally have less than 75K miles on it, for 4 decades of use.
Most RVs sit unused or in stationary occupation for all but a handful of days a year, when they are called upon to travel long distances. While that 8mpg RV looks like a more tempting target than the 32 mpg commuter car, it travels a short distance almost every day, and travels a lot more miles each year than the RV does.
Then you have the problem of recharging the batteries when you run out. If you are using the RV to travel from RV Park to RV Park, and the RV Parks are less than your battery distance away from each other, then you are good. If you are using the RV to go camping in a non-developed dispersed camping spot without infrastructure (“boon docking”), then this doesn’t work well, particularly if the vehicle drains that battery with your fridge, lighting, and cooking needs.
TBH, I am really looking forward to self-driving RVs. Not only would owning one rule (Sleeper car! Program it to get you to where you are going, go back and sleep, arrive in the morning fresh and ready for the day!) but it would also be cool since you wouldn’t have to dodge RVs driven by elderly people who shouldn’t be driving anything larger than a golf cart. (Sadly, I figure by the time that they have self-driving RVs, I’ll be one of those elderly people who shouldn’t be driving anything larger than a golf cart, so WIN WIN WIN. 
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