Bringing back fond memories of our own trip to Canada using this route back in 2011. Not sure if it was along your way, but you have already passed Lava Beds National Monument on the northern edge of CA by Tulelake. If you have any fancy for caving into tunnels made by ancient lava, that's an excellent place to go.

I trust you're using coastal Hwy 101 when coming back south, hehe.