Darcy/Thorin
Totally valid and something to take into consideration.
On the list of no's I'll give you now: Nothing too public, not that I think you'd do it anyway, but like, never proposal at a mall or a baseball game. At MOST, when close family and friends are around. People you're already comfortable with.
Never drop the ring in a glass of champagne. Or anything, really. No food involved. It's disaster waiting to happen.
For you two, I'd vote something quiet and sweet. Maybe at home so you don't have to worry about the scheduling thing? Or rent out a rooftop and decorate it in twinkle lights and candles and have a romantic dinner.
Maybe get her to take a weekend off and drag her to a super nice hotel room and pamper her?