on the plus side if forces a break every couple of hours.
That sounds good, but it's far too prescriptive and constricting. That might be a good average to kind of work around, but people aren't robots and it's much better when the driver/passengers can decide when they need a break rather than having to fall into line with the car's demands or when an algorithm insists on it.
I remember once printing out an AA route which involved a trip on a ferry. It very matter-of-factly told me where it was 'time for a break' after two hours of travel time had elapsed, except that the ferry journey took about 1h45m, so it was ordering me to stop for a break after nearly two hours of arduous relaxing in an armchair with a drink and sandwich and reading the paper!
I also had an Audi that would 'helpfully' and distractingly flash up '2 hrs' on the dashboard after the engine had been on for two hours. In doing this, it prevented it from communicating other important information for the driver, as the screen had now been hijacked. Of course, it had no idea if you were sitting in a gridlock unable to go anyhere, were only 5 minutes from your destination anyway or indeed had been swapping drivers every two hours without turning the engine off.
I think there are two possible solutions to the issue in the OP, though. I believe that one of the longer-term goals of 'smart' motorways is to facilitate wireless charging, so you won't even need to stop at all. I imagine this will also be the case with home/public car park charging, where there will eventually no need to actually connect the vehicle to the charging point, thus you could get loads of cars parked around one 'hub' within a reasonable range.
The other one, which I personally don't like the idea of at all, but I can see may be around the corner before too long, is to get out of the mindset of owning and being responsible for YOUR car and separating the two distinct needs of the travellers and their luggage with the provision of transport for them. Once cars are all driverless, they will be able to take themselves off empty to a charging point whenever they need it and then a replacement car will be able to bring itself over to where it's needed to transport people. They may even develop a way of automatically moving your bags from one boot to the other. Thus, as long as you don't mind/care/have any choice over which car you travel in, A car will serve you at every stretch along the way.
When they're properly here, driverless cars will have as much to do with eliminating the need to own cars as much as the need to drive them. Of course, that does rely on there being plenty to go around; otherwise, instead of sitting around waiting an hour for a point to charge your car, you'll just be sitting around waiting an hour for a replacement care to arrive....