KFCI on Sunday? Bring your appetite for Southern cooking. They've got an all you can eat Southern buffet (fried chicken, pulled pork, BBQ ribs, greens, beans, the works) at the King's Korner right in the airport terminal building. Mmmm, good, and only like $8 (might be a couple more on Sunday with an expanded buffet)! Might even be tempted to fly there just to meet you for lunch.
BTW, they're closed on Saturdays as catering is their main business, and that's their busy catering day for the week -- not enough staff to keep the restaurant open with all the off-site work.
OTOH, Richmond International (KRIC) has the Virginia Aviation Museum on the field (park at the FBO at the far corner at the north end to be right next door -- can't remember if that's MillionAir or Richmond Jet), which is well worth the trip (even if it will be pretty cold for looking at the SR-71 they have outside). Food is about a 10-minute walk across the street from the museum, with a wide range of places to eat. Only place I've been beyond that is Richmond International Raceway, but the NASCAR season doesn't start for a another month.