Hwy 261 from RItzville to Washtucna is a knuckle grabber. There's hills and corners and autopilot looses it. So, you have to actually DRIVE the car. It's not a pleasant drive. Google maps says that route is 34 minutes. To go back to freeway 395 to Washtunca for the easier drive is about an hour. That means a longer charge in Ritzville adding more to the delay. I have suggested to both Chambers of Commerce in Pullman and Colfax to approach Tesla to install a Supercharger. Colfax would be best as I could do a daily charge when coming in from Ellensburg for a football game and on the way back not have to do a nearly full charge to get back. Right now I have to scrounge around Pullman to get a slow daily charge and a slow full charge to get back.
I don't remember that being a tough drive at all. But yeah I generally don't recommend autopilot on country roads. Snow and winter driving conditions are another matter. Most Tesla owners making such a drive won't be doing it in winter.
But yeah there should definitely be a supercharger in Pullman. Would be a coup for Colfax if they could beat them to the punch, but Pullman would serve the whole area better. Most people going to the area would probably be going to Pullman anyway and it would be a reasonable detour for drivers travelling on US95 in Idaho.
Speaking of US 95, they could fairly easily "complete" US 95 by putting one near McCall and one somewhere near Grangeville (I'm not as familiar with that area as I haven't been through there since I was a kid). Those two along with Pullman/Moscow would connect CDA to Boise. Then one more in SE Oregon would connect Boise to Winnemucca. The rest of US 95 south to the Mexican border is basically already complete. They will probably add one in Blythe, CA with all the issues at Quartzsite, but even if they don't, Quartzsite is already relatively close the US 95 route.