Personally I think it sounds charming, fun and casual, I love the idea of weddings which are more like celebratory gatherings and less like formal stuffy affairs. But then, I'm not American so I have a different cultural take on this. (I guess you could tell your friends it's all the rage in Australia :-) .)

Most events like that here in California would only serve wine, maybe with beer, and not an open bar.

Offer wine (mainly white, some red), good beers, and the usual waters and sodas, plus some sparkling apple juice like Martinelli's.

Maybe you run with a more formal crowd, but it would be the norm here in Northern California.

Depends on your guests. Will there be underage people there? Will the drinking be responsible or get crazy? (And how can you predict that?) You may have legal responsibility for DUI's and worse. I would definitely have some control of the wine distribution, even if it has to be a friend or family member instead of a paid bartender. My experience is, there is always at least one guest who has to be tactfully cut off. Besides, you will need much more wine if it is just out there

Thanks for the encouragement (sushipup and ColleenOZ) and the warnings (Scarlett). Could I ask you all to describe how you think I should do it? The ceremony is off site, so people will be arriving at our house around 1 (after hiking up a long, steep driveway). There they will be offered some cool drinks which I think have to be passed on trays in glasses. Maybe those drinks could be water, lemonade, iced tea, sparkllng rose? Then I'm thinking lunch will be put out as a buffet, maybe from several different stations, for people to take plates to eat either at a table or a blanket, or anywhere else they want. Do you think the bottles of wine and interesting beers (small bottles or larger, for sharing?) should be chilling in some big barrels, next to a pile of blankets? Or should servers be assigned to circulate with them, pouring a glass or leaving the bottle on a table? Help me picture the whole scene, and how we can be gracious and casual, but not wasteful. When do toasts occur at a wedding like this? Our property is very spread out so once people take off it will be not be until cake time (inside) that we will be corralled back to one place. By the way, the bride and groom are Californians, so I love the idea of having a west coast vibe for this east coast event!

I have to get out of the house, but a couple of thoughts...

Sparkling Rose? No way. Yeah, there are acceptable ones now, but stick with good whites and reds. Even cheap champagne (bbut not too cheap) is okay. Go to a good wine shop and start doing a little tasting now.

And please provide tables and chairs for everyone over 10 years old. The "Picnic" theme is charming but PLEASE don't take it so far as blankets on the ground.

Toasts come after eating and before the cake is cut.

More later, if I can think of something.

I agree with sushipup.

I have been to many events with wine out on the tables, and it worked just fine.

Presumably children are either with their parents or at a children's table with no wine on it.

Avoid waste by limiting your offerings. Put on each table a pitcher of ice water, a pitcher of iced tea, and a couple of bottles of wine. Have more available for tables that need more.

I do hope you are assigning tables and having servers. A picnic is casual, but the problem of wandering around with a plate looking for a place to sit is identical no matter the level of formality. If you absolutely won't do that, then you absolutely need (1) lots of extra seats and (2) servers to clear away dirty dishes, cups, and napkins, so that the spaces can be used again.

You definitely need tables and chairs for everyone. The blanket idea might work for young children, but not for adults. As Sushipup said, the toasts occur at the time of the cake cutting, usually just before, so everyone is focused in one place for both activities. If you are having dancing, we often invite the couple to have their first dances after the cake cutting while the cake is being cut and served.

In most communities, when an event occurs on private property, you are not legally required to hire a bartender, but you then assume all the liability for any issues that may occur with a guest who over indulges, gets belligerant, or drinks and drives. If you have a paid bartender, they assume some of that liability. It is their responsibility to be watching those who drink. If you were having 80 guests, it would be easier to manage them, but with 180 and spread around the property, can you keep an eye on everyone?

You need to hire more several people. Someone will oversee the bottles of wine, kept behind the 'bar', and make sure they get to the tables. That's also where you'll keep barrels of ice with beers and sodas and water bottles. I would not put pitchers of water or tea on the tables unless you want flies in the brew. But if you do, someone needs to keep track of those, filled and empty glasses cleared away. Don't forget the recycling bins, clearly labeled.

Have a driver in a van at the bottom of the hill to ferry guests up your driveway. Those wearing high heels will thank you.

Keep the picnic theme with red-check tables cloths, maybe picnic basket flower arrangements.

There are ways to cut costs, but with 180 guests, it'll still be costly. But if the food is good and the wine doesn't run out, everyone will love it.

Just remember that the less people you hire, the more you will have to get "hands on" and micromanage. You're spending money on bartenders, yes, but they're taking a massive load off of your shoulders - the responsibility of alcohol serving. That's a big one. Whatever you decide, may it all go very well. :)