As with any wedding the venue is going to set the tone for the type of wedding that you are having. A fancy catering hall may not be your best option for a rustic wedding. Rustic weddings use items like wood, re-purpused furniture, lanterns, etc, that may not necessarily fit into a formal catering hall. Some areas of the country might lend broader options for rustic wedding than others, however if you look hard enough you can find the right location no matter where you are. Barns come to the forefront of my mind, but you can also consider vineyards, warehouses, and a local Bed and Breakfast and other old buildings.
The accessories that you can use to make this day come to life are limitless. Wedding decor can include jars with candles, re-purposed wood, old suit cases, trunks thrift store finds, even garage sale finds may prove useful. Sometimes you could take new things and make age them so they give the appearance they have been here a long time. You could find may weathering and aging techniques online depending on the product you want to age. Great opportunity to use something old and special to you , maybe and item or two from grandma's house. There are even places that will allow you to rental vintage items, it doesn't get easier than that.
Comfort foods come to mind when I think rustic, finding the right caterer will be important also to bring your theme alive through food. Serving in unusual containers and serving the non traditional could all play a part for your very rustic event
The important point is that you stay true to your theme and to yourselves as a couple, at the end of it all it is your wedding day and it is a reflection of you as a couple.
Vintage Rental Sites
Ribbons and Rust