Peddie is about 3 hrs and 10 minutes from Washington DC. It is co-ed and about 65% boarding. I would consider the boarding community quite strong. Weekends are busy! The also have a large endowment for financial aid.
*edited to fix a typo
When DS was applying we received information from
Christchurch School in VA, about an hour from Richmond. I know nothing about it except that it’s co-Ed day and boarding and looks like a beautiful location.