In my SR+ getting from Springfield to Grants Pass can be stressful. I'd prefer to be able to drive without range anxiety. It is the biggest gap along all of I-5 by a significant amount. Similarly, driving down the coast, the gap between Coos Bay and Lincoln City is by far the biggest gap on the coast highway. Coming from Eugene, I either need to stick close to Florence or plan to go all the way to Lincoln City or Coos Bay to visit the coast.
I agree that Springfield to Grants Pass could use another Supercharger Station in the middle — I could make it in my car, with much lower range (178 RM) and much lower efficiency than your SR+, but it isn't easy. Range anxiety in an SR+? That's a surprise. Maybe in winter with really poor weather, I suppose.
However, Bandon to Lincoln City is really easy, in part because the speeds on the coast highway are lower than typical I-5 speeds, so the distance doesn't matter as much, due to the reduced drag that greatly increases efficiency. Even Eugene to Florence and back is really easy for an SR+, so if you wanted to get to the coast and back home without charging it would depend on how far north or south from Florence you wanted to go. A loop of Eugene to Florence to Newport to Corvallis to Eugene would be easy in my car and trivial in an SR+. Even an out-and-back from Eugene to Coos Bay would be doable in my car and easy in an SR+.
With so many parts of the country under-served by Superchargers, your area is already relatively well covered IMO.