Dates will help, but because this is domestic first class (identified that way because the airlines almost certainly won't be using an international-type plane for the service but rather domestic-type planes with two-class cabins with a business product serving as first), I'd suggest that rather than focusing on the first-class (or business-class) cabin, you attempt to get the shortest flight possible for the most reasonable cost in coach and then spend the money on something like AA's Five Star Service, which will provide you with Admiral's Club access if you don't already have it through other avenues as well as departure, connection, and arrival assistance. I don't discount the value of a two-seat row for a couple celebrating a ten-year anniversary, but other than that, I'm not sure about the value of first-class in a domestic cabin, especially at five to eight times the cost of coach.

On the other hand, I do see value in lounge access and the personal touch that something like Five Star provides. And there are some flights out of DC that do not involve extended connection times, shortening the flight experience. I'd be more tempted to save the time and money for a unique experience on the ground.

Nonetheless, I do understand that a first-class experience might be the only thing that will work for your trip; I just thought I'd suggest alternatives that might be close while saving you some money that could go towards making the experience on the ground better.