I see that NASA's Wallops Island Facility has already been recommended, and that is very close to Chincoteague. It is also worth noting that there is a herd of wild ponies maintained within the Chincoteague National Wildlife Refuge that is usually accessible for viewing via a short hike. If you want to walk a real ocean beach in winter, then probably your best bet is to make the one hour drive from Chincoteague up to Ocean City one day. Besides the beach there is a long traditional boardwalk, although most (if not all) of the store will be closed.

I will also note a couple of worthwhile stops on the drive between Washington and Chincoteague. Both deserve two to three hours at least, so which you see and for how long will require some thought on your part, although you could easily include one each on the drive to Chincoteague and the drive back. The first is Annapolis, the capital of Maryland and home to the US Naval Academy. This is a wonderful walking town that retains much of its Colonial Era charm. The second is the town of St. Michaels on the Eastern Shore and home to the Chesapeake Bay Maritime Museum. St. Michaels is about 10 miles off US-50, reachable via MD-33 from Easton.

Finally, I will mention one other thing you might possibly enjoy on the drive, although I realize that this doesn't appeal to all. When you get to Salisbury, you can go through it or you can take the freeway-quality bypass around it to the east, OR you can take some local roads around it to the west and cross the Wicomico River on the Upper Ferry (not the Whitehaven Ferry, which is closed for the winter) a unique little two or three car ferry that will remind you that not everything is Interstates and high rise bridges.

AZBuck