So what's the deal with Baltimore? I have never been but I have been wanting to return to DC. Anyone experienced with flying in and out of Baltimore and the best way to get to DC hotel for sightseeing? Rent car, train? Any advice?
Here's my two cents and hopefully others will chime in. It is a little challenging to reach the city from BWI but with lower fares may be worth it.
As far as public transportation, you have three options, bus to metro, MARC train to union station (metro), Amtrak to union station (metro). With the Bus to Metro and MARC to Metro, each way would take about an hour and cost should be no more than $10. Amtrak depends on which train you catch (not unlike Europe). Cost vary but have an overall shorter time around 30 minutes. The Express trains run more than $30, but you can get a regional train in the $12-18 range depending on time of day (one way)
Taxi fairs will vary but can run somewhere on the order of $80+ one way.
Car rental is available but then you have issues of paying for parking (Driving distance is about 33-35 miles depending on where you are going in DC). I love the public transportation once I reach the city so wouldn't choose car rental. There is the Metro and the Circulator bus that will hit just about everything you need in Downtown. Plus, cab fares aren't too bad if something isn't convenient for you.