We did a few wineries in Northern VA. Naked Mountain and Rappahannock Cellars were two of our favorites:
http://www.virginiawine.org/regions/northern-virginia
Places are close together, so if you're truly tasting and pace yourselves, you can visit a few in a day. If you have an easy going toddler, you'll probably be fine, otherwise, I'd look for a sitter. Or do a wine festival this summer and bring your kid.
There's hiking in the Shenandoah National Park.
Don't have a recommendation of a place to stay though.