Zero has bikes that have over a 200 mile range — which I think is pretty impressive, and had me running calculations in my head over whether they might be viable commuter. But for touring, you’ve got the problems of charging time and availability of charging. How many times have you squeezed out a 200-mile run and stopped for gas, then paused for an extra 15 minutes to stretch before throwing a leg over for another 100, 200, etc… Now throw in the hitch than you can’t leave than station for another hour (more if they don’t have a dedicated recharge station). It kind of changes the focus of the trip.
If you haven’t watched it, check out the “Long Way Up”. It’s the fourth in the Ewan and Charlie series, and in this one (spoiler alert) they ride up from South America on electric Harley’s. It’s a great show, but it kind of turns into less of a motorcycle travelogue and more of a quest for electricity (IMHO).
I bet in 10 or 15 years we will look back at that show and wonder why it was so hard, but for now and for touring, I think electric limits your routes and distance.
Also, I’m a cheap bastard, and the electric bikes are so very precious. I can likely ride gas to end of my days for less than the cost of new long-distance electric. YMMV