edmunds did a cross country thing in a tesla 23 stops for charging
Distance: 3,331.9 miles
Total time: 67 hours, 21 minutes.
Driving time: 52 hours, 41 minutes
Average driving speed: 63.2 mph
Total Supercharger plug-In time: 14 hours, 40 minutes
Average Supercharger plug-in time: 38.3 minutes
Number of Other Stops: 0
Total energy consumption: 1.06 Megawatt-hours
Total fuel cost: $0 (thanks to Tesla's free Superchargers, available to all Tesla owners)
figure with our cmax, you'd get 500 miles per tank on highway milage so thats 6.6 stops for fuel (90 minutes). figure by the time you stop for food, potty add in another 6 more stops (2 hours)
I would really like to see this broken up differently. At least part of my problem, most people aren't going to drive without multiple overnight stops. In this example, if you are driving 11 hours a day, you would need roughly 4 overnight stops (666 miles per day @ 63 mph average speed). This eliminates 4 "charging stops" or, more likely 6, as you can get a full charge which gives you an extra 100 miles of range over the 30 minute charge. In this case, depending on how you like to travel, it may not add a lot of time; you'd just need at least two meal breaks of at least 30 minutes -- and an hour would help give you some extra miles before the next stop. Personally, I like at least 30 minutes for a meal just to be out of the car and not staring at the road.
Now, I'd likely try and do over 800 miles a day, to cut a day off. With a gas powered car, particularly a hybrid or diesel, this is much easier as you can spend more time driving. From my figures, with a Tesla you could start out the day going 300 miles, but then you'd need to charge (likely during lunch), but you'd still have 2 more times you'd have to charge the Tesla. 800 miles a day is about 13 hours of driving, at 63 mph; and adding an extra hour and a half of stops makes for an even longer day. The C-Max would only require one actual stop (though obviously you would take more), but it could cut an hour of extra time -- a 14 hour day instead of a 15 hour day.
Of course, I think the biggest point this demonstrates, when you start looking at it this way, is why people typically don't drive across the US, but fly instead.
As for the number of charging stations, this will improve as we get more electric vehicles. What will be interesting will be to see how many gasoline stations there are in 25 years. There are currently 150,000 gas stations in the US but that number has fallen for 11 consecutive years. Additionally most gas stations are now also convenience stores, as they no longer make enough on gasoline sales alone. The number of gas stations should continue to decline, even without factoring EVs, as cars keep getting more efficient.
The number of charging stations that will pop up is another question. The first problem is that you can "fill" your EV at home, eliminating some of the demand for charging stations. Additionally, the time element will change charging stations, as well. I suspect that many charging stations will eventually become part of various retail stores, such as malls or even big box stores; others will be part of "entertainment" venues and restaurants. People won't want to sit at the car while their car "fills", and it isn't required like it is with fuel pumps.
I wouldn't be surprised to see a national chains that already exist at many freeway exits, come out with a program to include charging stations -- and even to give a discount for people who eat at their restaurant while charging. I can easily see a company like McDonald's doing this, then there are other travel stops like Stuckey's, Cracker Barrel, etc.
So it will be interesting to see how things will change; particularly the how the ratio of gas stations to charging stations changes over time.