First, much thanks to all posters...I have gained invaluable info from so many of you.
Re. Mt. Rainier: We are considering driving from Seattle, but need to know whether parking is available there? Would it make much difference if we arrived on an August weekday vs. weekend?
If a bus trip would be more convenient, do you have input on the Gray Line tour vs. Seattle City Tours? SCT is more expensive, but offers buses with only 24 passengers. Thanks!

Do you mean is there parking available at Mt Rainier? If so, why yes. There are parking lots at the many different places you can stop and view the scenery, take hikes, visit lodges etc.

That said, lots and lots of people visit Mt. Rainier, and some of the more popular spots get pretty crowded later in the day, and of course the weekends are going to be worse. August in general is one of the best times to visit the Pacific Northwest, but if you can arrange to go on a weekday instead of weekend, try it.

And, to add to that, try very hard to get a nice early start and get your parking spot early I personally would drive if you have the option. Just don't trust GPS! Get a map and plan your trip first. Sadly a friend of mine took a group of school kids from England last spring, relied on GPS in the rental van, and it took him in horrible circles! It isn't hard to get to at all, I think if you just look at a regular map you will be fine.

Have a wonderful time, I'm jealous!

Sure there's parking. It's a big mountain(!) with lots of different areas of the park. I'd drive. It's easy and not too far (~2 hours).

Sorry, guess I was unclear. What I really meant was not "Does parking exist?" but "Will I be able to find a spot if I'm not there at the crack of dawn?" I had read (somewhere) that parking was difficult, and I was trying to get some more specific info as to when that might be true. If the parking situation is very frustrating all summer long, then perhaps I would take a bus tour to Mt. Rainier instead.

We went to Mt Rainier in June, staying over a Thursday night. We'd driven down from Vancouver so arrived mid afternoon. We had no trouble at all finding parking anywhere in the NP that afternoon or the following morning. We left about 11am. No problems finding our way there either without a GPS. Used directions off Michelin and a good map. It was very straightforward.

Parking at Paradise on a summer weekend used to be an exercise in frustration. Has that situation improved?

Whew! Glad you clarified your question, because I wondered!

As I mentioned, August is primetime in the PNW. If it were me, and I could only speak for myself, I would get a very early start if I wanted to go on an August weekend and not circle the parking lot for quite some time at Paradise and other places. If you go on a weekday, the crowds might be reduced somewhat.

If you don't want to worry about it, yes, you can let the bus drivers worry about it. Of course you are at their mercy as far as time schedules then, but maybe that will be okay fo you.