Wedding attire is Black Tie optional. Black-tie optional is a signal that the couple wants guests to dress up but doesn't want to require ultra-fancy attire. For women, this generally means a full-length silhouette. For men, a tux isn't required but welcomed.
Cocktail hour begins at 5pm, but guests can start arriving at 4:45pm.
Aldie Mansion is only down the road from both the church and downtown Doylestown. You could grab a drink in town (Chambers, 86 West, etc.), and then head back to Aldie Mansion for cocktail hour.