No experience at all.
My favorite area requires backpacking in. I've done it as a round trip day hike but it's pretty brutal. Climb 1700 feet in 3.5 miles, then back down 500 feet in a mile. Trail is pretty rough, big loose rocks, some places stairsteps in the rocks, plus it traps runoff so it continually gets carved deeper. There is another way in, not as steep, but a mile farther and more exposure to direct sun .. hotter.
There is no chicken out option. If you're not well on your way back to the trailhead 2 hours before dark, you are committed to staying. The trail is bad enough that a twisted or even broken ankle in the dark is a real good possibility. If you buy the ticket, you have to ride the train. I've had two fairly terrifying experiences in there. We had bipedal visitors the very first night I was ever there, at least 3 of them, and I got introduced to infrasound. It sucks. And the last night I spent there, last summer, started pretty cool with an hour or so of light wood knocks coming from 30 feet or so away in the dark while I laid in my sleeping bag and bivy. It stopped being cool when "whatever it was" decided to leave. It was the most chilling, "alien", crazy sound I've heard in over 50 years in the woods. I thought I knew what was knocking, now I'm not sure. 7-1/2 miles back to the trailhead, in the dark, on a barely maintained trail .. nope, the die was cast, we had to stay and ride it out. Fortunately nothing further happened.
MIB