I've driven that route; but I stopped overnight at a campground at Crater Lake, so I can't tell you how I did charge-wise.
Whether you will make it or not depends on speed and weather. If the weather is bad, you could always slow down, though that can be aggravating. I personally wouldn't take a trip that long without a backup charging plan. Fortunately, a backup plan is pretty easy as there is a KOA in Klamath Falls that I've used in the past; you should have a pretty good idea by then if you are going to need a charge or not. I think there was also a campground in Weed in case you just fall short, though I haven't used that one.
Have fun...