Admit it. You're planning four to seven days in which you won't see the outside of the convention center. Your stay in Baltimore is going to be devoted entirely to indoor pursuits.
Well, if you ride a motorcycle, you may be making a mistake. Baltimore is darn close to some of the best motorcycling roads in the United States. A morning out of the rarefied environment of the convention might well do you good!
First of all, the watchword of most motorcyclists is NO HIGHWAYS. I'd particularly warn against the Beltways, not just the Baltimore one, but especially the one that circumnavigates D.C. U.S. 95 is another interstate to avoid; straight, boring with lots and lots and lots of cages (cars). So these suggestions will, as much as possible, ignore interstate highways.
For a gentle morning or afternoon ride, you can head in almost any direction west of Baltimore. My favorite rides this close to the city are on the roads west of Fort Meade and Savage, Maryland.
Most of these roads have no names, so grab an DeLorme atlas and let the bike lead you. If you find yourself thirsty or hungry, a great repast can be had at the Olney Ale house, which combines local brewery beer with hearty entrees. The Ale House is located on Route 108 12 miles east of Route 97 in Olney, Maryland. Take Route 1 South to Route 32 West.
If you wish to venture a bit further afield, but still want to limit your ride to half a day, you can head north on Route 45 or 83 (if you really want a highway) to York in Pennsylvania, where Harley Davidson has its final assembly plant. Just east of here are the rolling fields of Pennsylvania Dutch country. The factory, just off Route 30 and east of Route 83, is open most weekdays. They have a museum and gift shop as well, and welcome riders of all makes.
A little more time up north can take you in to the Gettysburg area west of York. The battlefield itself is worth a visit, and the countryside is glorious. Another area for a day long ride is the Catoctin Mountain area west of Baltimore. Take Route 26 west from Baltimore until you reach Route 550 to get into the Catoctin area. The mountains are lovely; no wonder the presidential retreat, Camp David, is located here.
If your plans are slightly more ambitious, there is an obvious choice. Head south (you can take the dreaded highways or head out to Frederick on Route 40 then south on Route 15) into Virginia. Here you'll find yourself in Virgini hunt country, a land of rolling hills, wineries, antique stores, and mountain passes. Take Route 340 south from Frederick and you'll find yourself in Front Royal. This is the north end of six hundred miles of fantastic mountain road comprising the Skyline Drive and the Blue Ridge Parkway. These roads are legendary to motorcyclists worldwide. If you are coming to Baltimore from the south, you could do far worse than to travel up this route. But be careful, especially on Skyline Drive, for the speed police.
A great resource for riding in this area is Motorcycle Journeys Through the Appalachians (Whitehorse Press) by Dale Conyer.
On a final note, remember that all of the states mentioned have helmet laws in place as of this writing. Maryland additionally requires reflective material on your helmet. Be sure to look me up at the con, and keep the rubber side down!