TRISTAN: No, I think you two make a very cute couple. Is your horse and buggy parked outside? Got to get home for the barn raising?
Yet another reference to the Amish, who drive horse and buggies as their traditional form of transport.
A barn raising is a community activity whereby all the members get together to build (“raise”) a barn for one person or one family. Generally the men do the physical labour, while women provide food and drink; it’s a major social occasion. Barn raising was common in North America in the 18th and 19th centuries, while the Amish and Mennonite communities continue the practice today.
Tristan is implying that life in Stars Hollow must be both agrarian and hopelessly antiquated.
The Annotated Gilmore Girls 