@acpayne: When I saw your post I was worried you were going to have a lower budget than that! We live pretty close and searched all over Napa and Sonoma and couldn’t find anything in our budget, which is less than half of yours! But I did get the chance to see quite a few places.
Sonoma is beautiful and a little less expensive, but if your guests are flying in, napa is much closer to the airports. Napa passed a law many over 30 years ago against wineries having weddings so it can be hard to find a spot. Only places that had the docs to do it before that law can have them And they know they can charge a lot.
As far as cost, it all depends on where you want your money to go. We found rentals anywhere from $4,000-$15,000 depending on the size & time of year. One place that was only $4,000 in the off season asked us to only use their preferred caterers which started at $100 per person! There was just no way we could afford that with over 200 guests! But I would imagine if you’re out of state, your guest list will be smaller and I would check it out. It’s a pretty amazing place called cornerstone. It’s in Sonoma but not as deep as some of the other locations. I believe their summer fee is about $10,000 + catering, etc. http://www.cornerstonegardens.com/.
I have been to this place but didn’t look at it for a wedding. I’m not sure of cost but it is on the outskirts of napa so may be a little less http://www.themeritageresort.com/napa-valley-weddings/vineyard-weddings
This place is pretty incredible. If your guest list is small it could be in your range, otherwise it’s pretty pricey http://www.thecarnerosinn.com/weddings/napa-valley-weddings
I really wanted to check this one out but I believe the guest count was too low for us http://www.merryvale.com/
Brix is a restaurant with the most beautiful garden set in the middle of fields of vineyards and has incredible food! http://www.brix.com/privatedining/weddings/ Considering what they offer I think their prices are great. It was just too small for us.
V. Sattui is one of the most famous places here to do weddings. I actually didn’t even check them out. I’m not sure why but I think I just assumed it was expensive. http://www.vsattui.com/Weddings/Wedding-Blog
Also, in Sonoma county, just outside of Healdsburg, we really liked Soda Rock winery, but the caterer fee was a little high for us especially paired with the fact that many of our guests would have to drive over two hours to get there. Their location fee was pretty low. http://www.sodarockwinery.com/. Sodarock is part of the Wilson wineries which has some other venues that were nice, just too small for us.
I hope that helps or at least gives you some leads or ideas. We are frequent napa & Sonoma visitors since we live so close and are big wine fans. Let me know if you have any other questions about the area!