I go to Richmond often but couldn't tell you what the National even is so can't help you there. The Canal Walk is a beautiful walk if it's a nice day (and it's free). Lot's of good restaurants and shopping in Shockoe Bottom. There's a Civil War museum along the Canal Walk as well. There's a Farmer's/Flower Market on 17th Street:
Thursday Growers' Market 8:30 a.m. - 4:00 p.m.
Friday Red, White & Brew 5:00 p.m. - 9:00 p.m.
Saturday Growers' Market 9:00 a.m. - 4:00 p.m.
Sunday Vintage & Growers' Market 9:00 a.m. - 4:00 p.m.
Come to the market for access to the freshest, best-tasting, and most nutritious produce, eggs, meats, cheeses, baked goods and other prepared foods as well as locally handmade crafts.
They have outdoor concerts along Canal Walk too as well as boat tours (but I think walking it is better). If you cross over the James River (there's a walking only bridge that does) to Brown Island you can walk around and watch people tube, swim, kayak, etc. Always packed during the warmer days.