My .02. Tip the bike over on it's left side. Get stiff wire (coat hanger) and strong flashlight. You can bend the coat hanger various ways to reach crannies.. see if you can coax the penny to where you can see it. Maybe then you can get to it with mech fingers, hemostats, or the like. If not, then tip the bike backup then over so the penny comes closer to the oblong hole.
(Been there.. did that. What I lost was through the oblong hole was the little metal pin that held the tensioner compressed. THEN lost 2 magnets while trying to fish out that pin!!)
First thing that happens now, those holes get plugged with rags!