I've done dozens of weekend trips by bus and train. Amtrak goes all over in both directions (Philly. Baltimore, NYC, Wilmington, Richmond, Williamsburg, Charlottesville, Virginia Beach, Harpers Ferry, etc). Flix Bus and Megabus are also good options and I've met some really interesting international travelers, especially on the Flix Bus. Annapolis is $5 every day on the Flix Bus. VA Breeze gets you to tons of Virginia towns (Lexington, Blacksburg, Roanoke, etc) and runs every day. Lots of options!