You want Tesla's Chademo Adapter for road trips, it's like more range
I just completed a 5,000 mile road electric trip from California to British Columbia which was made possible by using Tesla's CHAdeMO adapter which lets me use the "other" network of DC Fast charging stations. Turns out this adapter is much more useful than you think, even though that network is inferior in just about every way. It's a must to roam British Columbia (where the DC Fast network is much larger than the Tesla one) but also very handy even in places where superchargers are common.
I have a few articles to write on this road trip. The first is about this adapter and using two networks. It can be found at Forbes.com at:
Plus enjoy a video from the trip with no connection to electric cars, other than no gasoline was burned to shoot it.