There was an article written by an attorney recently (last 12 months) about a similar incident in West Virginia/Virginia and Ohio. The basic gist of bike laws is this.

A bike is a car and is bound by those laws. States vary yes, but it's safer to make a blanket statement with that high of a bar.

Treat your bike as a car, front light, rear light, headlamp, and be visible. Don't give the fuzz any reason to give you crap.

As for impeding traffic flow, the article written I referenced above was written by a bike attorney and the laws of those states are written to say that a rider on a narrow road has to keep speed that is acceptable to that rider's level. So in the article they referenced two experienced riders that biked in national championships. They were keeping speed in line with their ability, 20 - 30 mph, in town which is not impeding, but had they been just skipping about at a leisurely pace, the cops would have had a leg to stand on.

My laws in Oregon are written to say that if the shoulder is not wide enough and it is not safe for a car to pass on the left that a bike should be in the center of the lane and act as a car. You could, as I do, ride closer to the shoulder because idiots like to fly around bikes so I give them room.