Getting Around in Washington D.C.

[Ricky's Girl]

We're planning to see a Washington National's game when we're in D.C. in September. I was wondering if we park at Union Station to tour the mall area earlier in the day can we then take a train from Union Station to the ballpark and back for a night game? Or is it easier just to park near the stadium? If so, any suggestions where to park? Are there any interesting shops or restaurants near the ball park in case we want to go earlier?

Also, can anyone reccommend any scrapbooking stores in the D.C. and Crofton, Maryland area?

Thanks!
Susie