I ride. A lot. And I try to carry whenever I can. I've tried all sorts of things. What I usually use is a Galco "explorer" shoulder holster or a strong side OWB with a thumb break. I move too much on my bike to trust something without a thumb break. Paddle holsters or any IWB will dig into me too much in the saddle. I had a 5.11 vest and some leather vest with pistol pockets and I just did not trust the little velcro straps that kept the pocket closed.
For those concerned about the safety of carrying in a crash - I know two people who wrecked while carrying. In neither case did the gun go off. One guy skid on his gun/holster for a while, nearly wearing a hole in the leather.
As far as where to put the gun when in MD - if you don't have luggage of some sort I have no idea. My bike has a little lockable tool compartment under the seat. A compact pistol might fit in there if the tools were taken out . . . Generally I just try to stay out of Maryland.