Short an easy, watch out for high waves. When standing on the rock I wouldn't suggest standing within a foot of anything wet (I know you're not an idiot). I was surprised a couple times by large waves that got to close for comfort when standing on the boulders.
This is not so much a trail as a dirt access road to the shoreline. We parked on the side of the dirt road where there were gateways for some of the houses. The walk to the shore itself is pretty uneventful and flat- you can admire some vegetation and look through the trees at the shoreline and some of the properties nearby. I would recommend either avoiding this road or using an ATV or truck with 4WD if it has recently rained. We got lucky and the road was dry and walkable. Even so there were many potholes filled with mud along the way. The view was amazing once we reached the shore. We spent a lot of time watching the powerful surf crash into the shoreline. If you plan on doing so, scout out the rocks to make sure that they won't get splashed by the waves. The first outcropping of black rocks, especially, got pounded by waves the entire time we were there. We didn't make it out to the tide pools because the surf was too unsafe, but on a calmer day, I can imagine they might be quite pleasant. All in all, on a dry day, this is a very easy walk that rewards you with a nice view of the coastline at the end.
Absolutely beautiful. May be a bit crowded because between the views and the show put on by the variety of sea birds at this refuge, it's an absolutely don't miss stop on Kauai. From Līhu‘e, drive north on Kūhiō Highway for approximately 23 miles to Kīlauea, turn right on Kolo Road, then left on Kīlauea Road and drive 2 miles to the refuge entrance. All visitors are required to drive down into the refuge parking area. Parking is limited. The walkway is paved. The Refuge is open Tuesday - Saturday, 10:00 am to 4:00 pm and is closed on Sunday and Monday and federal holidays. Admission is $5.00 per person - National Parks passes and all federal land passes are honored here. Allow at least 30 minutes to enjoy your time. Northern most point of main Hawaiian Islands. Self-guided tours only, can’t go to top of the lighthouse, but views from the bluff are worth your time. Don't miss it!