I hiked out to Liberty Cap from the north trailhead (about 5.5 mi), then took a short side trip to Otto's Bathtub on the way back.  Otto's Tub was definitely worth it!  Liberty Cap Trail was generally easy to follow.  The trail to Otto's Tub wasn't marked other than a small 3 stone cairn that is easy to miss.

The hike out to Tower Arch is fun and challenging, especially at the beginning.  The trail is well-marked, but there are places where you can get off-route so pay close attention to the cairns.  I got off-route and had to scramble unnecessarily.

This trail requires a permit which must be obtained in advance from recreation.gov.  At the time of this writing, the permit costs $10 per person (ages 5 yrs old and up).  Only 75 permits are issued per day so these permits can be hard to obtain in the busier months.

The Fiery Furnace is not really a hike, but more of a route finding adventure through a natural labyrinth of rock.  There is no trail, although there are some arrow markers that are strategically placed and show the way.  Still, it is very easy to get lost.  I recommend you download a GPX trackfile to your phone and put your app in Offline Mode so you can follow the route without relying on GPS (Note:  GPS signals are very inaccurate in slot canyons due to poor or non-existent signal).

I, personally, didn't find the Fiery Furnace as difficult as I thought it would be.  In fact, I intentionally took some off-route treks to explore hidden areas.