Believe it or not, it's easier to walk through the Paw Paw tunnel with no light. With a light, all you can see is what's within the beam. And even with a light, it's not advisable to ride through the tunnel because the path is narrow, uneven, and can be puddly. Just walk your bike through and look about 10-15 feet ahead of you, below the spot of sunlight coming through the entrance at the far end. Before you know it, your eyes will adjust to the darkness and you'll be able to see much more around you than you might expect.
And that's all the advice I can give on this topic. I'm sure other folks will have lots of suggestions for riding after sunset.