Hello! I was wondering about how the Kona did on a road trip too, so I went on a 1000 round trip road trip last December.
You can see how it went in this youtube video:
Pretty solid trip. Good to see that you're figuring out how to make the most of the car's charging limits and infrastructure and such. I make part of that trip (from about Frederick to Morgantown) every so often, although I haven't in a few months.
You noted in the video that there are now chargers at Deep Creek Lake in McHenry, Md., which will be a big help if/when you do the trip again. There are also another set of chargers in Hancock that are cheaper and faster than the Electric Vehicle Institute ones, a few blocks away. Both the McHenry and Hancock chargers are capable of up to 125 kW (if there isn't a car at the other charger -- 62.5 kW if not).
The Kona can DC charge at 77 kW, but only under certain circumstances. You should have been able to hit 77 at Electrify America, but maybe it was too cold.
Infrastructure: as it stands now, there are basically just three reasons for someone to build a charger (other than Tesla): Electrify America has to spend $2 billion because of Dieselgate, state grants and utilities. State grants are dependent on state policy, and West Virginia isn't very great on that front.
But the near future for utilities might hold some hope. Part of the area you covered is in American Electric Power's territory, and they're part of a coalition that just announced plans to build EV chargers along travel corridors:
https://electrek.co/2021/03/02/six-...ctric-highway-coalition-in-southeast-midwest/. So perhaps that will help.
And lastly, if the infrastructure bothers you enough, you could switch to a different route. Maybe take I-81 south to I-64, or stay on I-70 to Ohio and hop down to US 50.