I've done a 24 hr. solo ride (325 miles) on a road bike in New England a few years ago, in late October, so it was ~12+ hours of darkness, and on a secluded MUP trail system, that had no path-specific lighting. Lighting was key. 2 bar lights (one ON, and one reserve light OFF, or recharging off a battery pack in the saddle bag), and another smaller rechargeable light on top of the helmet for directional lighting.
Since I don't mind dark riding in general, on the commuter I have a dynamo to power the front/rear lights, just to guarantee that I always have lights, in case I'm held late at work unexpectedly, and didn't top off the recharge of the lights.
Night riding (or early morning twilight riding during a commute) definitely has less human traffic, but has an increase of wildlife activity (particularly the bunnies in the morning here) that are often much sketchier and twitchier than any human toddler, where they'll run next to you and then suddenly make a 90 degree turn and cross the trail right in front of your wheel, and I'm just waiting for the day when one jumps into my front wheel and takes me down at speed. For that reason, I try not to ride TO work in the dark, and shift my work hours throughout the year to accommodate daylight on both ends, but especially the mornings, and then deal with the dark on the night commute.