Skip Klamath Falls. You’re not missing anything.
I don’t know anything about Newberry Volcanics. However, the Lava Beds are a truly wonderful place. The caves are old lava tubes that get burned out every couple thousand year in eruptions, so there are no beautiful, fragile old cave structures. That means that there’s really nothing to hurt with your skin oils, so you can just grab a flashlight, a bike helmet, and go caving yourself-- no guides or paved trails. Tons of fun.
Definitely going to do Lava Beds soon, we’ll probably combine it with Lassen and Mt. Shasta.
One of the tubes at Lava Beds is set up so you don’t need a helmet or a flashlight–they have it lit with cool red neon lighting strips along the pathway. Also, if you use the southern access road to the park (to or from SR 139), watch your speed because there are some horrible potholes along the way.
If you are going to have internet access or a smart phone with you the following site shows road conditions and traffic delays. If you click on cameras you can view the various road cameras around the state.
I so miss living in Bend. The walk up to the top of Pilot Butte was one of my favorite things to do on a Sunday morning.
For food in Bend, I recommend the Deschutes Brewery Pub. Consistently good food.