I'm trying to find anyone that made it from Harris Ranch to the Roseville Super Charger, or vise versa. How many miles did you start with and how many did you end up with upon arrival?
I don't drive that direction from Harris Ranch, but I live 230 miles from Harris SC and I have always made it with 30 miles or so to spare. I drive 63 mph on cruise, which is smoother than my foot. Going in the slow lane, you drive along with the semis, and it is relaxing. Of course you know that pushing it at 75 or 80 you will run out of charge.
Going slower is still faster than going out of your way to get to the Vacaville SC.
Before you leave Harris, check your buffer. I use ideal miles (since I am getting about 300 miles per charge this way). It is about 210 miles to Roseville. If I get 260 ideal miles, then my buffer is 50. Ten miles up the road, I can look at my buffer again, and if it's dropping (like to 48 miles) then I drop my speed a notch. If your buffer is going up, then up the speed. Easy to arrive with exactly what you plan (I like to arrive with about 30 miles, so that's what I do).
Elevation doesn't change much to Roseville. But the little it may rise is why you have a buffer! It's easy, though. I would have no qualms doing 65 maybe, but I would drive it slower until I figure out what it takes for my car.
Also, you don't want to use heat at all, but these days that's not a problem. Light AC doesn't use much.\\
I see tbleakne beat me to this! But, yeah, I agree, you can make it.