My boyfriend and I are going to Baltimore for a wedding in a couple of weeks (May 19) and will arrive at BWI around 9AM. The wedding is the next day in Ellicot City. We are renting a car. We have the rest of that Friday (May 19) to see Baltimore (never been there before). While I feel like this is a dumb question, I wondered if anyone would care to comment on the following options:
1) should we take the light rail from BWI and do our sightseeing in Baltimore first and then go back to BWI and rent the car and drive to Columbia to our hotel, or
2) should we rent the car at BWI (keeping our luggage in the trunk) and drive in to the city, find a parking lot or garage, leave the car there for the day and explore Baltimore and then go to Columbia at the end of the day and get our hotel room or
3) should we rent the car, get the hotel room in Columbia, and then drive into Baltimore to do our sightseeing. They all seem to have pros and cons. Any suggestions on itinerary / sightseeing appreciated.

I vote for number 3 mainly because of the luggage issue. Columbia is only 20-30 min. from from BWI, and Baltimore is an easy drive from Columbia. You'll have to spend a little to park your car in Baltimore though.

I think that after you rent the car you should just head to Baltimore. As long as the luggage fits in the trunk, you are fine. With only one afternoon, my suggestion is to go to the Inner Harbor. The Preakness is that Saturday so expect it to be VERY crowded. If the weather cooperates, just spend time eating lunch outside and walking around. It is very lovely on the water. You can take a water taxi ride to Fells Point, walk around the shops there. That is where the TV show Homocide was shot. Then there's also Little Italy if you want good Italian. You just can't go wrong. (Can you tell I live here?)

Thanks so much for the feedback. Looks like we could find enought to keep us busy for an afternoon.

If you have the time, the National Aquarium in the inner harbor is a great way to kill a couple of hours. They just opened a new permanent exhibit called "Australia:land of extremes".
Harborplace next to the Aquarium is full of shops and nice restaurants.