The closest thing to VA-Beach any good for trail riding is Newport News.
Newport News:
1. Harwood Mills - on Old Denbiegh Blvd
2. Behind RiverSide Hospital, across from Mariners Museum, has some trails that are re-opened after being restricted for many years.
Williamsburg: Waller Mill “dogwood trail” - take the camp perry exit
There are several trails near the college
York River State Park: a few trails that are very good!