Drive From Seattle to Las Vegas - What To See? Where To Stay?

I really want to spend a night http://gccaverns.com/.

We always liked to stop at Summer Lake Hot Springs when we were roadtripping down there, it's not too far East of Crater Lake. Really nice family-owned desert ranch with indoor hot springs and bizarre scenery decorations - old rusted out tractors driven by pirate skeletons, that kind of thing. I've only camped there but I think they have cabins/trailers for rent overnight, or just stop for lunch and a dip in the afternoon.

At least make a side trip down the Columbia River Gorge. (I-84)

If you head toward Crater Lake, might want to consider the gorgeous and undervisited Lassen Volcanic Park, and at least drive near Shasta, which isn't far away. Also sort of en route is Yosemite, which might be a bit less crowded post Labor Day and start of school.

I would drive the PCH as far as Redwood National Forest. The PCH is fantastic - Redwood National Forest is even better.

From Reno, take the northern route (375 to 93 instead of the 95) and stop at the http://littlealeinn.com/ on the http://en.wikipedia.org/wiki/Nevada_State_Route_375.

Seconding Mannequito. The cabins at Summer Lake are neat. They are geo-thermically heated.

I went on a long road trip a few years ago and we also the little weird places. We had really good luck with this http://www.roadsideamerica.com/mobile/ It lists TONS of weird little places to visit and has a "near me" option of searching. Also, since you mention it's a roadtrip, we also made heavy use of http://iexitapp.com/, which tells you what stores, hotels, coffee shops, restaurants, gas stations you can find at upcoming exits, I can't recommend this one enough. You can see up to 100 exits ahead and can search for a particular store.

If you want really, really remote you can go through the Black Rock desert and see the Burning man site at Gerlach. It isn't much to see, but man is it in the middle of nowhere. The whole drive is worth doing once. From Crater lake go (in order) to Klamath falls, Alturas, Gerlach, Fernley, Fallon, Tonopah, Beatty, Las Vegas. When we drive from Eugene to Phoenix we go that route as it is the physically shortest and fastest depending on how much you are willing to speed. No traffic, it is all small towns with lots of little things to see along the way, but no real big tourist draw. Fernly/Fallon is almost exactly halfway between Eugene/Phoenix and either one has hotels and restaurants (and not much else). Check out the route on Google Maps (true for all the suggested routes) and decide what you want to see (HINT:In Nevada it is a whole lot of desert-with semi inhabited Ghost towns dispersed more or less evenly).