12 Could Be A Crowd..
 

But my mother would like our family to spend her 65th birthday together somewhere in the Western United States (we are in California). Can anyone come up with a place where renting a house/cabin for that many people wouldn't be prohibitively expensive? Ages range from 2 years old to 65 years old. We've already thought of Tahoe/Big Bear/Mammoth, but are looking for other places that we just may not know about. It will be for August 2011, and she would prefer no National Parks, so count those out. Any help greatly appreciated! Thanks!

I think you will find a number of possibles on vrbo. The area around Bend, OR, the Cascades and McCall, ID are worth checking.

"<i> . . . for that many people wouldn't be prohibitively expensive?</i>"

can't help too much unless we know what you consider prohibitively expensive. What is your budget?

also--in many parts of the country August is the highest of high season. If budget is a big issue, any chance to move the celebration to September or some other time?

I don't know about the cost (the accommodations range in size, style and price), but we went for several years running to Black Butte near Bend, Oregon -- it's a self-contained resort with houses, condos, cabins, maybe even a hotel (not sure), tennis courts, bike paths, golf courses, pools, etc. We had a great time (always went with 3 families). Sunriver would be similar, but I think it's much bigger.

http://www.blackbutteranch.com/

@janisj- I'm guessing our budget would top out at 3,000 for a week's rental.

@janisj- Oops, didn't see your other post! It can't be moved to September, as too many of the party will either be teaching school or in school. It's a good idea and we would definitely have done it that way if it had been feasible.

@sf7307- Thanks for the suggestion and link, I will definitely check it out!

@cmcfong- I'm not familiar with vrbo, so thanks for the tip!

Sunriver is larger-140 homes/condos available for rent. 2 golf courses, Deschutes River and a small airport available.
sunriver-resort.com 1 866 556-9395

@tomfuller- Thanks, I'll definitely check it out.

Can't suggest a specific spot, but would like to add a few comments.

August was mentioned as being high season. We have found that many ski resorts offer very good rates in the summer for lodging. I realize more and more are trying to develop into year round resorts, but not all.

I know you asked about a house for 12 people, but perhaps you may want to consider separate condos so you all can have a good time together, but still go home as friends.

We stayed in a small condo in Park City, which was fine for two of us. However, it connected to a much larger unit, which could be a good idea for families being together. The younger children could go to bed in safety and quiet while the adults partied on.

I'm sure someone out there could suggest a place.

Clousie is right, there is a lodge/hotel at the place where you check in and get the map to the house/condo you reserved.
I live not too far away so I never stayed there. Some people stay there when they ski at Mt. Bachelor.